chromium/third_party/blink/web_tests/external/wpt/resources/webidl2/lib/README.md

This directory contains a built version of the [webidl2.js library](https://github.com/w3c/webidl2.js).
It is built by running `npm run build-debug` at the root of that repository.

The `webidl2.js.headers` file is a local addition to ensure the script is interpreted as UTF-8.