# Engine assets

Regex Tools executes ECMAScript through the browser's native `RegExp` engine.
It also ships three declared, self-hosted runtime packs:

- `pcre2/`: official PCRE2 10.47, 8-bit WebAssembly;
- `python/`: Pyodide 314.0.3 with CPython 3.14.2 `re`; and
- `java/`: TeaVM 0.15.0's `java.util.regex` class library compiled to an
  ES2015 module. This module is not OpenJDK.

The packs come from pinned, documented open-source inputs. Runtime files travel
with deterministic metadata, closed-set checksums and the applicable upstream
licence/notice material, all of which are verified by the release gate.