In the article https://v8.dev/blog/v8-extras, the URLs for promise.js, uri.js, bootstrapper.cc, ReadableStream.js etc are broken since they link to https://code.google.com/p/chromium/codesearch#chromium/src/v8/src/js/promise.js which redirects to https://source.chromium.org/chromium#chromium/src/v8/src/js/promise.js and the files no longer exist.

The links could be changed to specific tagged version of source like https://chromium.googlesource.com/v8/v8.git/+/refs/tags/5.0.1/src/js/promise.js