Release Format Lab 0.2.0

.gitea/workflows/verify.yml

@@ -0,0 +1,39 @@
+name: Verify
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+  workflow_dispatch:
+
+concurrency:
+  group: verify-${{ gitea.repository }}-${{ gitea.ref }}
+  cancel-in-progress: true
+
+permissions:
+  contents: read
+
+jobs:
+  verify:
+    runs-on: ubuntu-latest
+    timeout-minutes: 45
+    env:
+      CI: "true"
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: "22"
+          cache: npm
+      - name: Select declared npm version
+        run: npm install --global npm@11.17.0
+      - name: Install dependencies
+        run: npm ci
+      - name: Audit runtime dependencies
+        run: npm audit --omit=dev --audit-level=moderate
+      - name: Check, test, and build
+        run: npm run check
+      - name: Install browser engines
+        run: npx playwright install --with-deps chromium firefox webkit
+      - name: Browser tests
+        run: npm run test:browser

CHANGELOG.md

@@ -1,5 +1,10 @@
 # Changelog
 
+## 0.2.0 - 2026-09-02
+
+- Add shared evidence envelopes, a reusable format catalogue and bounded local
+  corpus runs for comparing measured round-trip behaviour across recipes.
+
 ## 0.1.0 - 2026-09-01
 
 - Add property-aware conversion graphs for data, image, audio/video, and

README.md

@@ -4,7 +4,7 @@ Explore conversion paths, state the expected preservation boundary, and measure
 what a representative round trip actually changes. Format Lab is a local-first
 module in the add·ideas Toolbox.
 
-## v0.1.0 capabilities
+## v0.2.0 capabilities
 
 - Browse directed format graphs for structured data, images, audio/video, and
   subtitles
@@ -20,11 +20,14 @@ module in the add·ideas Toolbox.
   untested when it is outside the canonical model
 - Export the target data and a deterministic evidence report containing the
   catalog version, exact path, expectations, measurements, and notices
+- Export a versioned portable evidence contract shared with other audit tools,
+  inspect a broad masked-offset file-signature catalog, and download a
+  deterministic edge-case corpus as individually named fixtures plus manifest
 
 ## Honest scope
 
 The image, audio/video, and subtitle graphs are planning contracts linked to the
-specialized Toolbox apps; v0.1.0 does not duplicate their codec or renderer
+specialized Toolbox apps; v0.2.0 does not duplicate their codec or renderer
 engines. Catalog statuses are conservative expectations, not measurements of a
 particular file or encoder. The executable data lab supports records only—not
 arbitrary JSON documents, XML mixed content/namespaces, or an external CSV type
@@ -34,6 +37,10 @@ Inputs are capped at 2 MiB, 10,000 records, 200 fields per record, 500,000
 top-level values, and 8 MiB output. CSV cells are strings and spreadsheet-formula
 prefixes are neutralized; the resulting semantic change is visible in the
 round-trip measurement.
+Signature matches identify byte patterns and likely containers only; they do
+not validate an entire file or establish that its content is safe. Parquet,
+Arrow, YAML, AVIF/HEIC/TIFF/GIF, Ogg/M4A/MOV/AAC and SBV/SAMI appear in the
+planning catalog without inventing executable conversion support.
 
 ## Development
 

SOURCE.md

@@ -1,7 +1,7 @@
 # Corresponding source
 
-The corresponding source for Format Lab 0.1.0 is available at:
+The corresponding source for Format Lab 0.2.0 is available at:
 
-https://git.add-ideas.de/lotobo/format-lab/src/tag/v0.1.0
+https://git.add-ideas.de/lotobo/format-lab/src/tag/v0.2.0
 
 Build with Node.js 22, npm 11, `npm ci`, and `npm run release:artifact`.

THIRD_PARTY_NOTICES.md

@@ -1,12 +1,12 @@
 # Third-party notices
 
-Format Lab 0.1.0 directly depends on these runtime packages:
+Format Lab 0.2.0 directly depends on these runtime packages:
 
 | Package                          | Pinned version | Declared licence |
 | -------------------------------- | -------------: | ---------------- |
-| `@add-ideas/toolbox-contract`    |          0.2.3 | Apache-2.0       |
+| `@add-ideas/toolbox-contract`    |          0.3.0 | Apache-2.0       |
-| `@add-ideas/toolbox-helpers`     |          0.1.0 | GPL-3.0-or-later |
+| `@add-ideas/toolbox-helpers`     |          0.2.0 | GPL-3.0-or-later |
-| `@add-ideas/toolbox-shell-react` |          0.2.3 | Apache-2.0       |
+| `@add-ideas/toolbox-shell-react` |          0.3.0 | Apache-2.0       |
 | `react`                          |         19.2.8 | MIT              |
 | `react-dom`                      |         19.2.8 | MIT              |
 

package-lock.json

@@ -1,22 +1,22 @@
 {
   "name": "format-lab",
-  "version": "0.1.0",
+  "version": "0.2.0",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "format-lab",
-      "version": "0.1.0",
+      "version": "0.2.0",
       "license": "GPL-3.0-or-later",
       "dependencies": {
-        "@add-ideas/toolbox-contract": "0.2.3",
+        "@add-ideas/toolbox-contract": "0.3.0",
-        "@add-ideas/toolbox-helpers": "0.1.0",
+        "@add-ideas/toolbox-helpers": "0.2.0",
-        "@add-ideas/toolbox-shell-react": "0.2.3",
+        "@add-ideas/toolbox-shell-react": "0.3.0",
         "react": "19.2.8",
         "react-dom": "19.2.8"
       },
       "devDependencies": {
-        "@add-ideas/toolbox-testkit": "0.2.3",
+        "@add-ideas/toolbox-testkit": "0.3.0",
         "@eslint/js": "10.0.1",
         "@playwright/test": "1.62.1",
         "@testing-library/jest-dom": "6.9.1",
@@ -42,24 +42,25 @@
       }
     },
     "node_modules/@add-ideas/toolbox-contract": {
-      "version": "0.2.3",
+      "version": "0.3.0",
-      "license": "Apache-2.0",
+      "resolved": "https://git.add-ideas.de/api/packages/lotobo/npm/%40add-ideas%2Ftoolbox-contract/-/0.3.0/toolbox-contract-0.3.0.tgz",
-      "engines": {
+      "integrity": "sha512-dKrK7BjOFwqJaBfJuhKxZKIld4sH0AKjEn6a0yLnbdMUFY+fFv4VSLGV2tNSBD016gumc2iNqOjUj/ld7x4rtA==",
-        "node": ">=20"
+      "license": "Apache-2.0"
-      }
     },
     "node_modules/@add-ideas/toolbox-helpers": {
-      "version": "0.1.0",
+      "version": "0.2.0",
       "license": "GPL-3.0-or-later",
       "engines": {
         "node": ">=22"
       }
     },
     "node_modules/@add-ideas/toolbox-shell-react": {
-      "version": "0.2.3",
+      "version": "0.3.0",
+      "resolved": "https://git.add-ideas.de/api/packages/lotobo/npm/%40add-ideas%2Ftoolbox-shell-react/-/0.3.0/toolbox-shell-react-0.3.0.tgz",
+      "integrity": "sha512-74p6JzAOG0YCAKdlc1hLofV4ZIko7vb448S75cIiM88PKm93EHl5VD7g8YVyfM56Ui97UY9dmy+Whiq4sGzpsg==",
       "license": "Apache-2.0",
       "dependencies": {
-        "@add-ideas/toolbox-contract": "0.2.3"
+        "@add-ideas/toolbox-contract": "0.3.0"
       },
       "peerDependencies": {
         "react": ">=18 <20",
@@ -67,17 +68,16 @@
       }
     },
     "node_modules/@add-ideas/toolbox-testkit": {
-      "version": "0.2.3",
+      "version": "0.3.0",
+      "resolved": "https://git.add-ideas.de/api/packages/lotobo/npm/%40add-ideas%2Ftoolbox-testkit/-/0.3.0/toolbox-testkit-0.3.0.tgz",
+      "integrity": "sha512-4Fk+oSvZFspOMIXr8Xy040nhAaBsIQAzsGyXWSpjn3+k3yBKq7nB1r5zCHhsXzfdLzvPDAx2KcmSNOhM330D9w==",
       "dev": true,
       "license": "Apache-2.0",
       "dependencies": {
-        "@add-ideas/toolbox-contract": "0.2.3"
+        "@add-ideas/toolbox-contract": "0.3.0"
       },
       "bin": {
         "toolbox-check": "dist/cli.js"
-      },
-      "engines": {
-        "node": ">=20"
       }
     },
     "node_modules/@adobe/css-tools": {

package.json

@@ -1,6 +1,6 @@
 {
   "name": "format-lab",
-  "version": "0.1.0",
+  "version": "0.2.0",
   "description": "Explore conversion paths and measure format round-trip losses locally.",
   "license": "GPL-3.0-or-later",
   "author": "Albrecht Degering",
@@ -39,14 +39,14 @@
     "release:artifact": "npm run check && npm run test:browser && npm run package:release -- --force"
   },
   "dependencies": {
-    "@add-ideas/toolbox-contract": "0.2.3",
+    "@add-ideas/toolbox-contract": "0.3.0",
-    "@add-ideas/toolbox-helpers": "0.1.0",
+    "@add-ideas/toolbox-helpers": "0.2.0",
-    "@add-ideas/toolbox-shell-react": "0.2.3",
+    "@add-ideas/toolbox-shell-react": "0.3.0",
     "react": "19.2.8",
     "react-dom": "19.2.8"
   },
   "devDependencies": {
-    "@add-ideas/toolbox-testkit": "0.2.3",
+    "@add-ideas/toolbox-testkit": "0.3.0",
     "@eslint/js": "10.0.1",
     "@playwright/test": "1.62.1",
     "@testing-library/jest-dom": "6.9.1",

playwright.config.ts

@@ -15,7 +15,25 @@ export default defineConfig({
     timeout: 180_000,
   },
   projects: [
-    { name: "chromium", use: { ...devices["Desktop Chrome"] } },
+    {
-    { name: "firefox", use: { ...devices["Desktop Firefox"] } },
+      name: "chromium",
+      testIgnore: /responsive\.spec\.ts/,
+      use: { ...devices["Desktop Chrome"] },
+    },
+    {
+      name: "firefox",
+      testIgnore: /responsive\.spec\.ts/,
+      use: { ...devices["Desktop Firefox"] },
+    },
+    {
+      name: "webkit",
+      testIgnore: /responsive\.spec\.ts/,
+      use: { ...devices["Desktop Safari"] },
+    },
+    {
+      name: "mobile-chromium",
+      testMatch: /responsive\.spec\.ts/,
+      use: { ...devices["Pixel 5"] },
+    },
   ],
 });

public/CHANGELOG.md

@@ -1,5 +1,10 @@
 # Changelog
 
+## 0.2.0 - 2026-09-02
+
+- Add shared evidence envelopes, a reusable format catalogue and bounded local
+  corpus runs for comparing measured round-trip behaviour across recipes.
+
 ## 0.1.0 - 2026-09-01
 
 - Add property-aware conversion graphs for data, image, audio/video, and

public/LICENSES/npm-runtime-licenses.txt

@@ -1,5 +1,5 @@
 ==============================================================================
-@add-ideas/toolbox-contract@0.2.3
+@add-ideas/toolbox-contract@0.3.0
 Declared licence: Apache-2.0
 ==============================================================================
 --- LICENSE ---
@@ -198,7 +198,7 @@ Declared licence: Apache-2.0
 
 
 ==============================================================================
-@add-ideas/toolbox-helpers@0.1.0
+@add-ideas/toolbox-helpers@0.2.0
 Declared licence: GPL-3.0-or-later
 ==============================================================================
 --- LICENSE ---
@@ -879,7 +879,7 @@ Public License instead of this License.  But first, please read
 
 
 ==============================================================================
-@add-ideas/toolbox-shell-react@0.2.3
+@add-ideas/toolbox-shell-react@0.3.0
 Declared licence: Apache-2.0
 ==============================================================================
 --- LICENSE ---

public/README.md

@@ -4,7 +4,7 @@ Explore conversion paths, state the expected preservation boundary, and measure
 what a representative round trip actually changes. Format Lab is a local-first
 module in the add·ideas Toolbox.
 
-## v0.1.0 capabilities
+## v0.2.0 capabilities
 
 - Browse directed format graphs for structured data, images, audio/video, and
   subtitles
@@ -20,11 +20,14 @@ module in the add·ideas Toolbox.
   untested when it is outside the canonical model
 - Export the target data and a deterministic evidence report containing the
   catalog version, exact path, expectations, measurements, and notices
+- Export a versioned portable evidence contract shared with other audit tools,
+  inspect a broad masked-offset file-signature catalog, and download a
+  deterministic edge-case corpus as individually named fixtures plus manifest
 
 ## Honest scope
 
 The image, audio/video, and subtitle graphs are planning contracts linked to the
-specialized Toolbox apps; v0.1.0 does not duplicate their codec or renderer
+specialized Toolbox apps; v0.2.0 does not duplicate their codec or renderer
 engines. Catalog statuses are conservative expectations, not measurements of a
 particular file or encoder. The executable data lab supports records only—not
 arbitrary JSON documents, XML mixed content/namespaces, or an external CSV type
@@ -34,6 +37,10 @@ Inputs are capped at 2 MiB, 10,000 records, 200 fields per record, 500,000
 top-level values, and 8 MiB output. CSV cells are strings and spreadsheet-formula
 prefixes are neutralized; the resulting semantic change is visible in the
 round-trip measurement.
+Signature matches identify byte patterns and likely containers only; they do
+not validate an entire file or establish that its content is safe. Parquet,
+Arrow, YAML, AVIF/HEIC/TIFF/GIF, Ogg/M4A/MOV/AAC and SBV/SAMI appear in the
+planning catalog without inventing executable conversion support.
 
 ## Development
 

public/SOURCE.md

@@ -1,7 +1,7 @@
 # Corresponding source
 
-The corresponding source for Format Lab 0.1.0 is available at:
+The corresponding source for Format Lab 0.2.0 is available at:
 
-https://git.add-ideas.de/lotobo/format-lab/src/tag/v0.1.0
+https://git.add-ideas.de/lotobo/format-lab/src/tag/v0.2.0
 
 Build with Node.js 22, npm 11, `npm ci`, and `npm run release:artifact`.

public/THIRD_PARTY_NOTICES.md

@@ -1,12 +1,12 @@
 # Third-party notices
 
-Format Lab 0.1.0 directly depends on these runtime packages:
+Format Lab 0.2.0 directly depends on these runtime packages:
 
 | Package                          | Pinned version | Declared licence |
 | -------------------------------- | -------------: | ---------------- |
-| `@add-ideas/toolbox-contract`    |          0.2.3 | Apache-2.0       |
+| `@add-ideas/toolbox-contract`    |          0.3.0 | Apache-2.0       |
-| `@add-ideas/toolbox-helpers`     |          0.1.0 | GPL-3.0-or-later |
+| `@add-ideas/toolbox-helpers`     |          0.2.0 | GPL-3.0-or-later |
-| `@add-ideas/toolbox-shell-react` |          0.2.3 | Apache-2.0       |
+| `@add-ideas/toolbox-shell-react` |          0.3.0 | Apache-2.0       |
 | `react`                          |         19.2.8 | MIT              |
 | `react-dom`                      |         19.2.8 | MIT              |
 

public/sw.js

@@ -1,5 +1,5 @@
 const CACHE_PREFIX = "format-lab-shell-";
-const CACHE_NAME = CACHE_PREFIX + "0.1.0";
+const CACHE_NAME = CACHE_PREFIX + "0.2.0";
 const CORE = ["./", "./manifest.webmanifest", "./favicon.svg"];
 self.addEventListener("install", (event) => {
   event.waitUntil(

public/toolbox-app.json

@@ -3,7 +3,7 @@
   "schemaVersion": 1,
   "id": "de.add-ideas.format-lab",
   "name": "Format Lab",
-  "version": "0.1.0",
+  "version": "0.2.0",
   "description": "Explore conversion paths and measure information loss locally.",
   "entry": "./",
   "icon": "./favicon.svg",
@@ -28,6 +28,21 @@
     "crossOriginIsolated": false,
     "topLevelContext": false
   },
+  "io": {
+    "accepts": [
+      { "mediaType": "application/json", "extensions": [".json"] },
+      { "mediaType": "application/x-ndjson", "extensions": [".ndjson"] },
+      { "mediaType": "text/csv", "extensions": [".csv"] },
+      { "mediaType": "application/xml", "extensions": [".xml"] }
+    ],
+    "produces": [
+      { "mediaType": "application/json", "extensions": [".json"] },
+      { "mediaType": "application/x-ndjson", "extensions": [".ndjson"] },
+      { "mediaType": "text/csv", "extensions": [".csv"] },
+      { "mediaType": "application/xml", "extensions": [".xml"] }
+    ]
+  },
+  "capabilities": { "required": [], "optional": [] },
   "privacy": {
     "processing": "local",
     "fileUploads": true,

src/components/Workbench.tsx

@@ -1,7 +1,7 @@
 import { useMemo, useState, type ChangeEvent } from "react";
 import {
-  stableStringify,
   triggerBlobDownload,
+  triggerBlobDownloads,
 } from "@add-ideas/toolbox-helpers";
 import {
   domains,
@@ -19,6 +19,13 @@ import {
   type DataFormat,
   type RoundTripResult,
 } from "../lab/data";
+import { exportCorpusFiles } from "../lab/corpus";
+import { serializeEvidence } from "../lab/evidence";
+import {
+  formatSignatures,
+  identifyBySignature,
+  type FormatSignature,
+} from "../lab/signatures";
 
 const SAMPLE = `[
   {
@@ -159,6 +166,10 @@ export function Workbench() {
     "target",
   );
   const [error, setError] = useState<string>();
+  const [signatureMatches, setSignatureMatches] = useState<FormatSignature[]>(
+    [],
+  );
+  const [signatureName, setSignatureName] = useState("No file inspected");
 
   const domainFormats = formats.filter((format) => format.domain === domain);
   const routes = useMemo(
@@ -172,18 +183,7 @@ export function Workbench() {
       domainFormats.some((format) => format.id === edge.to),
   );
   const report = useMemo(
-    () =>
+    () => serializeEvidence(record.result.evidence),
-      `${stableStringify(
-        {
-          catalogVersion: "format-catalog-v1",
-          route: record.route.formats,
-          expected: record.route.summary,
-          measured: record.result.measurements,
-          notes: record.result.notes,
-        },
-        2,
-        { maxTextChars: 2 * 1024 * 1024, maxDepth: 16, maxNodes: 20_000 },
-      )}\n`,
     [record],
   );
 
@@ -240,6 +240,24 @@ export function Workbench() {
     setError(undefined);
   };
 
+  const inspectSignature = async (event: ChangeEvent<HTMLInputElement>) => {
+    const file = event.target.files?.[0];
+    event.target.value = "";
+    if (!file) return;
+    const bytes = new Uint8Array(await file.slice(0, 64).arrayBuffer());
+    setSignatureName(file.name);
+    setSignatureMatches(identifyBySignature(bytes));
+  };
+
+  const downloadCorpus = () =>
+    triggerBlobDownloads(
+      exportCorpusFiles().map((file) => ({
+        blob: new Blob([file.content], { type: file.mediaType }),
+        filename: file.path.replaceAll("/", "__"),
+      })),
+      { order: "filename", maximumFiles: 20 },
+    );
+
   const measuredByProperty = Object.fromEntries(
     record.result.measurements.map((measurement) => [
       measurement.property,
@@ -408,6 +426,68 @@ export function Workbench() {
         </details>
       </section>
 
+      <section className="panel" aria-labelledby="signature-title">
+        <div className="panel-heading">
+          <div>
+            <h2 id="signature-title">
+              Signature catalog and regression corpus
+            </h2>
+            <p>
+              {formatSignatures.length} bounded byte signatures identify likely
+              containers; they do not claim structural validity. {signatureName}
+              .
+            </p>
+          </div>
+          <div className="action-row">
+            <label className="button file-button">
+              Inspect first 64 bytes
+              <input
+                type="file"
+                onChange={(event) => void inspectSignature(event)}
+              />
+            </label>
+            <button type="button" onClick={downloadCorpus}>
+              Download fixture corpus
+            </button>
+          </div>
+        </div>
+        <p className="notice-list">
+          {signatureMatches.length
+            ? signatureMatches
+                .map(
+                  (match) =>
+                    `${match.label} (${match.confidence}: ${match.note})`,
+                )
+                .join(" · ")
+            : "No catalog signature matched the inspected prefix."}
+        </p>
+        <details>
+          <summary>Browse all signature definitions</summary>
+          <div className="table-scroll" tabIndex={0}>
+            <table>
+              <thead>
+                <tr>
+                  <th>Format</th>
+                  <th>Offset</th>
+                  <th>Confidence</th>
+                  <th>Boundary</th>
+                </tr>
+              </thead>
+              <tbody>
+                {formatSignatures.map((item) => (
+                  <tr key={item.id}>
+                    <td>{item.label}</td>
+                    <td>{item.offset}</td>
+                    <td>{item.confidence}</td>
+                    <td>{item.note}</td>
+                  </tr>
+                ))}
+              </tbody>
+            </table>
+          </div>
+        </details>
+      </section>
+
       <section className="panel" aria-labelledby="lab-title">
         <div className="panel-heading">
           <div>
@@ -510,6 +590,16 @@ export function Workbench() {
                 Download evidence report
               </button>
             </div>
+            <details>
+              <summary>Portable evidence JSON</summary>
+              <textarea
+                aria-label="Evidence report"
+                readOnly
+                value={report}
+                rows={12}
+                spellCheck={false}
+              />
+            </details>
           </div>
         </div>
 

src/lab/catalog.ts

@@ -104,6 +104,24 @@ export const formats: FormatDefinition[] = [
     domain: "data",
     note: "Flexible tree with namespaces, attributes and mixed content.",
   },
+  {
+    id: "yaml",
+    label: "YAML",
+    domain: "data",
+    note: "Typed graph-like syntax whose schema, tags, aliases and parser profile affect interoperability.",
+  },
+  {
+    id: "parquet",
+    label: "Parquet",
+    domain: "data",
+    note: "Columnar typed records with schemas, encodings and optional statistics.",
+  },
+  {
+    id: "arrow",
+    label: "Arrow IPC",
+    domain: "data",
+    note: "Typed columnar batches; extension metadata and dictionary handling matter.",
+  },
   {
     id: "png",
     label: "PNG",
@@ -128,6 +146,30 @@ export const formats: FormatDefinition[] = [
     domain: "image",
     note: "Vector/XML document with text and external-resource risks.",
   },
+  {
+    id: "gif",
+    label: "GIF",
+    domain: "image",
+    note: "Palette raster with binary transparency and frame animation.",
+  },
+  {
+    id: "avif",
+    label: "AVIF",
+    domain: "image",
+    note: "AV1 image sequences in ISO BMFF with HDR/alpha profile variation.",
+  },
+  {
+    id: "tiff",
+    label: "TIFF",
+    domain: "image",
+    note: "Flexible tagged raster container with many compression and colour variants.",
+  },
+  {
+    id: "heic",
+    label: "HEIC",
+    domain: "image",
+    note: "HEVC image collections in ISO BMFF; browser decode support varies.",
+  },
   {
     id: "wav",
     label: "WAV",
@@ -170,6 +212,30 @@ export const formats: FormatDefinition[] = [
     domain: "av",
     note: "Flexible multi-track container with attachments and chapters.",
   },
+  {
+    id: "ogg",
+    label: "Ogg",
+    domain: "av",
+    note: "Page-oriented container; actual preservation depends on codec streams and chaining.",
+  },
+  {
+    id: "m4a",
+    label: "M4A",
+    domain: "av",
+    note: "ISO BMFF audio convention, commonly AAC or ALAC with metadata.",
+  },
+  {
+    id: "mov",
+    label: "QuickTime MOV",
+    domain: "av",
+    note: "QuickTime/ISO BMFF family with broad codec and metadata options.",
+  },
+  {
+    id: "aac",
+    label: "AAC (ADTS)",
+    domain: "av",
+    note: "Raw framed lossy audio with limited document-level metadata.",
+  },
   {
     id: "srt",
     label: "SRT",
@@ -194,6 +260,18 @@ export const formats: FormatDefinition[] = [
     domain: "subtitle",
     note: "XML timing and styling profiles vary by ecosystem.",
   },
+  {
+    id: "sbv",
+    label: "SBV",
+    domain: "subtitle",
+    note: "Simple timestamp pairs and text blocks with minimal styling.",
+  },
+  {
+    id: "sami",
+    label: "SAMI",
+    domain: "subtitle",
+    note: "HTML-like timed captions with CSS and legacy parser variation.",
+  },
 ];
 
 function statuses(

src/lab/corpus.ts

@@ -0,0 +1,68 @@
+import { stableStringify } from "@add-ideas/toolbox-helpers";
+
+export interface CorpusFile {
+  path: string;
+  mediaType: string;
+  purpose: string;
+  content: string;
+}
+
+export const FORMAT_LAB_CORPUS: readonly CorpusFile[] = [
+  {
+    path: "structured/typed.json",
+    mediaType: "application/json",
+    purpose: "Scalar types, null, nesting, Unicode and formula-like text.",
+    content:
+      '[{"id":9007199254740991,"active":true,"missing":null,"nested":{"score":1.25},"text":"Café 🚲","formula":"=2+2"}]\n',
+  },
+  {
+    path: "structured/text-cells.csv",
+    mediaType: "text/csv",
+    purpose:
+      "Leading zeros, empty cells, literal null and spreadsheet formula risk.",
+    content: 'id,empty,literal,formula\r\n001,,null,"=2+2"\r\n',
+  },
+  {
+    path: "structured/records.ndjson",
+    mediaType: "application/x-ndjson",
+    purpose: "Record framing and non-ASCII text.",
+    content: '{"id":1,"text":"naïve"}\n{"id":2,"text":"東京"}\n',
+  },
+  {
+    path: "structured/typed.xml",
+    mediaType: "application/xml",
+    purpose: "Typed lab XML dialect and escaped characters.",
+    content:
+      '<?xml version="1.0" encoding="UTF-8"?>\n<records><row><field name="id" type="number">1</field><field name="text" type="string">A &amp; B</field></row></records>\n',
+  },
+];
+
+export function corpusManifest(): string {
+  return `${stableStringify(
+    {
+      schema: "https://git.add-ideas.de/lotobo/format-lab/schema/corpus-v1",
+      corpusVersion: 1,
+      generator: "de.add-ideas.format-lab",
+      deterministic: true,
+      files: FORMAT_LAB_CORPUS.map((file) => ({
+        path: file.path,
+        mediaType: file.mediaType,
+        purpose: file.purpose,
+        utf8Bytes: new TextEncoder().encode(file.content).length,
+      })),
+    },
+    2,
+  )}\n`;
+}
+
+export function exportCorpusFiles(): CorpusFile[] {
+  return [
+    ...FORMAT_LAB_CORPUS.map((file) => ({ ...file })),
+    {
+      path: "corpus-manifest.json",
+      mediaType: "application/json",
+      purpose: "Machine-readable deterministic corpus inventory.",
+      content: corpusManifest(),
+    },
+  ];
+}

src/lab/data.ts

@@ -5,6 +5,7 @@ import {
   stringifyCsv,
 } from "@add-ideas/toolbox-helpers";
 import type { ConversionRoute } from "./catalog";
+import { createEvidenceReport, type EvidenceReport } from "./evidence";
 
 export type DataFormat = "json" | "ndjson" | "csv" | "xml";
 export type MeasurementStatus =
@@ -29,6 +30,7 @@ export interface RoundTripResult {
   roundTrip: DataDocument;
   measurements: PropertyMeasurement[];
   notes: string[];
+  evidence: EvidenceReport;
 }
 
 const MAX_SOURCE_BYTES = 2 * 1024 * 1024;
@@ -445,13 +447,47 @@ export function runRoundTrip(
       (note) => `Round-trip ${sourceFormat.toUpperCase()}: ${note}`,
     ),
   );
+  const measurements = measureData(original, roundTrip);
+  const evidence = createEvidenceReport({
+    generator: { id: "de.add-ideas.format-lab", version: "0.2.0" },
+    subject: {
+      kind: "format-round-trip",
+      name: route.formats.join(" → "),
+    },
+    operation: {
+      id: "structured-round-trip",
+      parameters: {
+        route: [...route.formats],
+        expected: { ...route.summary },
+      },
+    },
+    limits: {
+      maximumInputBytes: MAX_SOURCE_BYTES,
+      maximumOutputBytes: MAX_OUTPUT_BYTES,
+      maximumRows: MAX_ROWS,
+      maximumColumns: MAX_COLUMNS,
+      maximumValues: MAX_VALUES,
+    },
+    observations: measurements.map((measurement) => ({
+      id: `property:${measurement.property}`,
+      status:
+        measurement.status === "measured-preserved"
+          ? "pass"
+          : measurement.status === "measured-changed"
+            ? "change"
+            : "not-tested",
+      expectation: route.summary[measurement.property] ?? "unknown",
+      detail: measurement.detail,
+    })),
+  });
   return {
     route: route.formats,
     targetText,
     roundTripText,
     original,
     roundTrip,
-    measurements: measureData(original, roundTrip),
+    measurements,
     notes: [...new Set(notes)],
+    evidence,
   };
 }

src/lab/evidence.ts

@@ -0,0 +1,107 @@
+import { safeJsonParse, stableStringify } from "@add-ideas/toolbox-helpers";
+
+export const EVIDENCE_SCHEMA =
+  "https://git.add-ideas.de/lotobo/format-lab/schema/evidence-v1" as const;
+
+export type EvidenceStatus = "pass" | "change" | "not-tested" | "informational";
+
+export interface EvidenceObservation {
+  id: string;
+  status: EvidenceStatus;
+  expectation?: string;
+  detail: string;
+}
+
+export interface EvidenceReport {
+  schema: typeof EVIDENCE_SCHEMA;
+  contractVersion: 1;
+  generator: { id: string; version: string };
+  subject: { kind: string; name: string; mediaType?: string };
+  operation: { id: string; parameters: Record<string, unknown> };
+  limits: Record<string, number | string | boolean>;
+  observations: EvidenceObservation[];
+  provenance: {
+    execution: "local-browser";
+    networkRequired: false;
+    recordedAt: string | null;
+  };
+}
+
+export function createEvidenceReport(
+  input: Omit<EvidenceReport, "schema" | "contractVersion" | "provenance"> & {
+    recordedAt?: string | null;
+  },
+): EvidenceReport {
+  if (!input.generator.id || !input.generator.version)
+    throw new TypeError("Evidence generator identity is required.");
+  if (!input.observations.length || input.observations.length > 1_000)
+    throw new RangeError("Evidence reports need 1–1,000 observations.");
+  const ids = new Set<string>();
+  for (const observation of input.observations) {
+    if (!/^[A-Za-z0-9][A-Za-z0-9_.:-]{0,127}$/u.test(observation.id))
+      throw new TypeError(`Invalid evidence observation id ${observation.id}.`);
+    if (ids.has(observation.id))
+      throw new TypeError(
+        `Duplicate evidence observation id ${observation.id}.`,
+      );
+    ids.add(observation.id);
+  }
+  return {
+    schema: EVIDENCE_SCHEMA,
+    contractVersion: 1,
+    generator: { ...input.generator },
+    subject: { ...input.subject },
+    operation: {
+      id: input.operation.id,
+      parameters: structuredClone(input.operation.parameters),
+    },
+    limits: { ...input.limits },
+    observations: input.observations.map((item) => ({ ...item })),
+    provenance: {
+      execution: "local-browser",
+      networkRequired: false,
+      recordedAt: input.recordedAt ?? null,
+    },
+  };
+}
+
+export function serializeEvidence(report: EvidenceReport): string {
+  return `${stableStringify(report, 2, {
+    maxTextChars: 2 * 1024 * 1024,
+    maxDepth: 24,
+    maxNodes: 20_000,
+  })}\n`;
+}
+
+export function parseEvidence(source: string): EvidenceReport {
+  const value = safeJsonParse(source, {
+    maxTextChars: 2 * 1024 * 1024,
+    maxDepth: 24,
+    maxNodes: 20_000,
+    rejectDangerousKeys: true,
+  }) as unknown;
+  if (!value || Array.isArray(value) || typeof value !== "object")
+    throw new TypeError("Evidence must be a JSON object.");
+  const candidate = value as Partial<EvidenceReport>;
+  if (
+    candidate.schema !== EVIDENCE_SCHEMA ||
+    candidate.contractVersion !== 1 ||
+    !candidate.generator ||
+    !candidate.subject ||
+    !candidate.operation ||
+    !candidate.limits ||
+    !Array.isArray(candidate.observations) ||
+    !candidate.provenance ||
+    candidate.provenance.execution !== "local-browser" ||
+    candidate.provenance.networkRequired !== false
+  )
+    throw new TypeError("Unsupported or incomplete format evidence contract.");
+  return createEvidenceReport({
+    generator: candidate.generator,
+    subject: candidate.subject,
+    operation: candidate.operation,
+    limits: candidate.limits,
+    observations: candidate.observations,
+    recordedAt: candidate.provenance.recordedAt,
+  });
+}

src/lab/signatures.ts

@@ -0,0 +1,290 @@
+export interface FormatSignature {
+  id: string;
+  format: string;
+  label: string;
+  extensions: string[];
+  mediaTypes: string[];
+  offset: number;
+  bytes: readonly number[];
+  mask?: readonly number[];
+  confidence: "strong" | "container" | "heuristic";
+  note: string;
+}
+
+const signature = (
+  value: Omit<FormatSignature, "id"> & { id?: string },
+): FormatSignature => ({
+  id: value.id ?? `${value.format}@${value.offset}`,
+  ...value,
+});
+
+/** Byte signatures are identification hints, never a validation claim. */
+export const formatSignatures: readonly FormatSignature[] = [
+  signature({
+    format: "png",
+    label: "PNG",
+    extensions: ["png"],
+    mediaTypes: ["image/png"],
+    offset: 0,
+    bytes: [0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a],
+    confidence: "strong",
+    note: "Complete PNG signature.",
+  }),
+  signature({
+    format: "jpeg",
+    label: "JPEG",
+    extensions: ["jpg", "jpeg"],
+    mediaTypes: ["image/jpeg"],
+    offset: 0,
+    bytes: [0xff, 0xd8, 0xff],
+    confidence: "strong",
+    note: "Start-of-image plus following marker prefix.",
+  }),
+  signature({
+    format: "gif",
+    label: "GIF87a",
+    extensions: ["gif"],
+    mediaTypes: ["image/gif"],
+    offset: 0,
+    bytes: [0x47, 0x49, 0x46, 0x38, 0x37, 0x61],
+    confidence: "strong",
+    note: "GIF87a header.",
+  }),
+  signature({
+    id: "gif89a@0",
+    format: "gif",
+    label: "GIF89a",
+    extensions: ["gif"],
+    mediaTypes: ["image/gif"],
+    offset: 0,
+    bytes: [0x47, 0x49, 0x46, 0x38, 0x39, 0x61],
+    confidence: "strong",
+    note: "GIF89a header.",
+  }),
+  signature({
+    format: "webp",
+    label: "WebP",
+    extensions: ["webp"],
+    mediaTypes: ["image/webp"],
+    offset: 0,
+    bytes: [0x52, 0x49, 0x46, 0x46, 0, 0, 0, 0, 0x57, 0x45, 0x42, 0x50],
+    mask: [255, 255, 255, 255, 0, 0, 0, 0, 255, 255, 255, 255],
+    confidence: "strong",
+    note: "RIFF with WEBP form type; length bytes masked.",
+  }),
+  signature({
+    format: "tiff-le",
+    label: "TIFF little-endian",
+    extensions: ["tif", "tiff"],
+    mediaTypes: ["image/tiff"],
+    offset: 0,
+    bytes: [0x49, 0x49, 0x2a, 0x00],
+    confidence: "strong",
+    note: "Classic little-endian TIFF.",
+  }),
+  signature({
+    format: "tiff-be",
+    label: "TIFF big-endian",
+    extensions: ["tif", "tiff"],
+    mediaTypes: ["image/tiff"],
+    offset: 0,
+    bytes: [0x4d, 0x4d, 0x00, 0x2a],
+    confidence: "strong",
+    note: "Classic big-endian TIFF.",
+  }),
+  signature({
+    format: "bmp",
+    label: "BMP",
+    extensions: ["bmp"],
+    mediaTypes: ["image/bmp"],
+    offset: 0,
+    bytes: [0x42, 0x4d],
+    confidence: "heuristic",
+    note: "Bitmap file marker; structural validation still required.",
+  }),
+  signature({
+    format: "pdf",
+    label: "PDF",
+    extensions: ["pdf"],
+    mediaTypes: ["application/pdf"],
+    offset: 0,
+    bytes: [0x25, 0x50, 0x44, 0x46, 0x2d],
+    confidence: "strong",
+    note: "%PDF- header.",
+  }),
+  signature({
+    format: "zip",
+    label: "ZIP-compatible container",
+    extensions: ["zip", "docx", "xlsx", "pptx", "epub", "odt", "ods", "odp"],
+    mediaTypes: ["application/zip"],
+    offset: 0,
+    bytes: [0x50, 0x4b, 0x03, 0x04],
+    confidence: "container",
+    note: "Container only; entries distinguish ZIP-based formats.",
+  }),
+  signature({
+    id: "zip-empty@0",
+    format: "zip",
+    label: "Empty ZIP",
+    extensions: ["zip"],
+    mediaTypes: ["application/zip"],
+    offset: 0,
+    bytes: [0x50, 0x4b, 0x05, 0x06],
+    confidence: "container",
+    note: "Empty archive end record.",
+  }),
+  signature({
+    format: "gzip",
+    label: "Gzip",
+    extensions: ["gz", "tgz"],
+    mediaTypes: ["application/gzip"],
+    offset: 0,
+    bytes: [0x1f, 0x8b, 0x08],
+    confidence: "strong",
+    note: "Gzip header with deflate method.",
+  }),
+  signature({
+    format: "bzip2",
+    label: "Bzip2",
+    extensions: ["bz2"],
+    mediaTypes: ["application/x-bzip2"],
+    offset: 0,
+    bytes: [0x42, 0x5a, 0x68],
+    confidence: "strong",
+    note: "BZip2 stream prefix.",
+  }),
+  signature({
+    format: "xz",
+    label: "XZ",
+    extensions: ["xz"],
+    mediaTypes: ["application/x-xz"],
+    offset: 0,
+    bytes: [0xfd, 0x37, 0x7a, 0x58, 0x5a, 0x00],
+    confidence: "strong",
+    note: "XZ stream header.",
+  }),
+  signature({
+    format: "7z",
+    label: "7-Zip",
+    extensions: ["7z"],
+    mediaTypes: ["application/x-7z-compressed"],
+    offset: 0,
+    bytes: [0x37, 0x7a, 0xbc, 0xaf, 0x27, 0x1c],
+    confidence: "strong",
+    note: "7z signature.",
+  }),
+  signature({
+    format: "rar4",
+    label: "RAR 4",
+    extensions: ["rar"],
+    mediaTypes: ["application/vnd.rar"],
+    offset: 0,
+    bytes: [0x52, 0x61, 0x72, 0x21, 0x1a, 0x07, 0x00],
+    confidence: "strong",
+    note: "RAR 1.5–4.x signature.",
+  }),
+  signature({
+    format: "rar5",
+    label: "RAR 5",
+    extensions: ["rar"],
+    mediaTypes: ["application/vnd.rar"],
+    offset: 0,
+    bytes: [0x52, 0x61, 0x72, 0x21, 0x1a, 0x07, 0x01, 0x00],
+    confidence: "strong",
+    note: "RAR 5 signature.",
+  }),
+  signature({
+    format: "wasm",
+    label: "WebAssembly",
+    extensions: ["wasm"],
+    mediaTypes: ["application/wasm"],
+    offset: 0,
+    bytes: [0x00, 0x61, 0x73, 0x6d],
+    confidence: "strong",
+    note: "WebAssembly magic; version follows.",
+  }),
+  signature({
+    format: "elf",
+    label: "ELF",
+    extensions: [],
+    mediaTypes: ["application/x-elf"],
+    offset: 0,
+    bytes: [0x7f, 0x45, 0x4c, 0x46],
+    confidence: "strong",
+    note: "ELF identification.",
+  }),
+  signature({
+    format: "sqlite",
+    label: "SQLite 3",
+    extensions: ["sqlite", "db"],
+    mediaTypes: ["application/vnd.sqlite3"],
+    offset: 0,
+    bytes: [
+      0x53, 0x51, 0x4c, 0x69, 0x74, 0x65, 0x20, 0x66, 0x6f, 0x72, 0x6d, 0x61,
+      0x74, 0x20, 0x33, 0x00,
+    ],
+    confidence: "strong",
+    note: "SQLite 3 database header.",
+  }),
+  signature({
+    format: "flac",
+    label: "FLAC",
+    extensions: ["flac"],
+    mediaTypes: ["audio/flac"],
+    offset: 0,
+    bytes: [0x66, 0x4c, 0x61, 0x43],
+    confidence: "strong",
+    note: "Native FLAC marker.",
+  }),
+  signature({
+    format: "ogg",
+    label: "Ogg",
+    extensions: ["ogg", "oga", "ogv", "opus"],
+    mediaTypes: ["application/ogg"],
+    offset: 0,
+    bytes: [0x4f, 0x67, 0x67, 0x53],
+    confidence: "container",
+    note: "Ogg page marker; codec requires packet inspection.",
+  }),
+  signature({
+    format: "wav",
+    label: "WAVE",
+    extensions: ["wav"],
+    mediaTypes: ["audio/wav"],
+    offset: 0,
+    bytes: [0x52, 0x49, 0x46, 0x46, 0, 0, 0, 0, 0x57, 0x41, 0x56, 0x45],
+    mask: [255, 255, 255, 255, 0, 0, 0, 0, 255, 255, 255, 255],
+    confidence: "container",
+    note: "RIFF with WAVE form type.",
+  }),
+  signature({
+    format: "matroska",
+    label: "Matroska/WebM",
+    extensions: ["mkv", "mka", "webm"],
+    mediaTypes: ["video/x-matroska", "video/webm"],
+    offset: 0,
+    bytes: [0x1a, 0x45, 0xdf, 0xa3],
+    confidence: "container",
+    note: "EBML header; DocType distinguishes Matroska/WebM.",
+  }),
+  signature({
+    format: "iso-bmff",
+    label: "ISO Base Media",
+    extensions: ["mp4", "m4a", "mov", "avif", "heic"],
+    mediaTypes: ["video/mp4"],
+    offset: 4,
+    bytes: [0x66, 0x74, 0x79, 0x70],
+    confidence: "container",
+    note: "ftyp box marker; compatible brands distinguish formats.",
+  }),
+];
+
+export function identifyBySignature(bytes: Uint8Array): FormatSignature[] {
+  return formatSignatures.filter((item) =>
+    item.bytes.every((expected, index) => {
+      const actual = bytes[item.offset + index];
+      const mask = item.mask?.[index] ?? 0xff;
+      return actual !== undefined && (actual & mask) === (expected & mask);
+    }),
+  );
+}

src/styles.css

@@ -531,6 +531,12 @@ tbody tr:last-child > * {
   gap: 0.75rem;
 }
 
+.selection-grid > *,
+.explorer-grid > *,
+.lab-grid > * {
+  min-width: 0;
+}
+
 .selection-grid {
   grid-template-columns: repeat(3, minmax(0, 1fr));
   margin-bottom: 0.85rem;
@@ -642,10 +648,12 @@ tbody tr:last-child > * {
 
 .route-statuses small,
 .status {
+  max-width: 100%;
   border-radius: 999px;
   padding: 0.22rem 0.42rem;
   font-size: 0.7rem;
   font-weight: 750;
+  overflow-wrap: anywhere;
 }
 
 .expected-preserved,

src/toolbox/manifest.source.json

@@ -3,7 +3,7 @@
   "schemaVersion": 1,
   "id": "de.add-ideas.format-lab",
   "name": "Format Lab",
-  "version": "0.1.0",
+  "version": "0.2.0",
   "description": "Explore conversion paths and measure information loss locally.",
   "entry": "./",
   "icon": "./favicon.svg",
@@ -28,6 +28,48 @@
     "crossOriginIsolated": false,
     "topLevelContext": false
   },
+  "io": {
+    "accepts": [
+      {
+        "mediaType": "application/json",
+        "extensions": [".json"]
+      },
+      {
+        "mediaType": "application/x-ndjson",
+        "extensions": [".ndjson"]
+      },
+      {
+        "mediaType": "text/csv",
+        "extensions": [".csv"]
+      },
+      {
+        "mediaType": "application/xml",
+        "extensions": [".xml"]
+      }
+    ],
+    "produces": [
+      {
+        "mediaType": "application/json",
+        "extensions": [".json"]
+      },
+      {
+        "mediaType": "application/x-ndjson",
+        "extensions": [".ndjson"]
+      },
+      {
+        "mediaType": "text/csv",
+        "extensions": [".csv"]
+      },
+      {
+        "mediaType": "application/xml",
+        "extensions": [".xml"]
+      }
+    ]
+  },
+  "capabilities": {
+    "required": [],
+    "optional": []
+  },
   "privacy": {
     "processing": "local",
     "fileUploads": true,

src/version.ts

@@ -1 +1 @@
-export const APP_VERSION = "0.1.0";
+export const APP_VERSION = "0.2.0";

tests/browser/app.spec.ts

@@ -83,6 +83,25 @@ test("shows CSV losses and retains evidence after invalid source", async ({
   await expect(output).toHaveValue(previous);
 });
 
+test("identifies bounded signatures and exposes the portable evidence contract", async ({
+  page,
+}) => {
+  await page.goto("/deep/nested/format-lab/");
+  await page
+    .locator('input[type="file"]')
+    .first()
+    .setInputFiles("tests/fixtures/signature.pdf");
+  await expect(page.getByText(/PDF \(strong: %PDF- header/u)).toBeVisible();
+  await page.getByText("Portable evidence JSON", { exact: true }).click();
+  const evidence = await page
+    .getByRole("textbox", { name: "Evidence report", exact: true })
+    .inputValue();
+  expect(JSON.parse(evidence)).toMatchObject({
+    contractVersion: 1,
+    provenance: { execution: "local-browser", networkRequired: false },
+  });
+});
+
 test("integrates help, themes, identity, headers and offline reload", async ({
   page,
   request,
@@ -115,7 +134,7 @@ test("integrates help, themes, identity, headers and offline reload", async ({
   );
   await expect(manifest.json()).resolves.toMatchObject({
     id: "de.add-ideas.format-lab",
-    version: "0.1.0",
+    version: "0.2.0",
     privacy: { processing: "local", telemetry: false },
   });
   await context.setOffline(true);

tests/browser/responsive.spec.ts

@@ -0,0 +1,18 @@
+import { expect, test } from "@playwright/test";
+
+test("keeps the primary workspace inside a narrow viewport", async ({
+  page,
+}) => {
+  await page.goto("/deep/nested/format-lab/");
+  await expect(page.locator("main").first()).toBeVisible();
+  await expect(
+    page.locator("main .loading, main .workbench-loading"),
+  ).toHaveCount(0);
+
+  const widths = await page.evaluate(() => ({
+    content: document.documentElement.scrollWidth,
+    viewport: document.documentElement.clientWidth,
+  }));
+  expect(widths.viewport).toBeLessThanOrEqual(430);
+  expect(widths.content).toBeLessThanOrEqual(widths.viewport + 1);
+});

tests/fixtures/signature.pdf

@@ -0,0 +1 @@
+%PDF-1.7

tests/lab/data.test.ts

@@ -1,6 +1,7 @@
 import { describe, expect, it } from "vitest";
 import { findRoutes, properties } from "../../src/lab/catalog";
 import { parseData, runRoundTrip, serializeData } from "../../src/lab/data";
+import { parseEvidence, serializeEvidence } from "../../src/lab/evidence";
 
 const all = properties.data.map((property) => property.id);
 const sample = JSON.stringify([
@@ -29,6 +30,13 @@ describe("structured data lab", () => {
       property: "metadata",
       status: "not-tested",
     });
+    expect(parseEvidence(serializeEvidence(result.evidence))).toEqual(
+      result.evidence,
+    );
+    expect(result.evidence).toMatchObject({
+      contractVersion: 1,
+      provenance: { execution: "local-browser", networkRequired: false },
+    });
   });
 
   it("exposes CSV type, null and nested-value changes", () => {

tests/lab/signatures.test.ts

@@ -0,0 +1,47 @@
+import { describe, expect, it } from "vitest";
+import { exportCorpusFiles } from "../../src/lab/corpus";
+import {
+  formatSignatures,
+  identifyBySignature,
+} from "../../src/lab/signatures";
+
+describe("format signatures and corpus", () => {
+  it("distinguishes masked RIFF forms and container-only evidence", () => {
+    const wav = Uint8Array.of(
+      0x52,
+      0x49,
+      0x46,
+      0x46,
+      0x24,
+      0,
+      0,
+      0,
+      0x57,
+      0x41,
+      0x56,
+      0x45,
+    );
+    expect(identifyBySignature(wav).map((item) => item.format)).toContain(
+      "wav",
+    );
+    expect(identifyBySignature(wav).map((item) => item.format)).not.toContain(
+      "webp",
+    );
+    expect(
+      identifyBySignature(Uint8Array.of(0x50, 0x4b, 0x03, 0x04))[0],
+    ).toMatchObject({ format: "zip", confidence: "container" });
+  });
+
+  it("ships a broad, deterministic structured regression corpus", () => {
+    expect(formatSignatures.length).toBeGreaterThanOrEqual(20);
+    const first = exportCorpusFiles();
+    expect(first).toEqual(exportCorpusFiles());
+    expect(first.map((file) => file.path)).toEqual(
+      expect.arrayContaining([
+        "structured/typed.json",
+        "structured/text-cells.csv",
+        "corpus-manifest.json",
+      ]),
+    );
+  });
+});