chromium/third_party/blink/web_tests/virtual/shadow-realm-enabled/README.md

ShadowRealm is a TC39 proposal ongoing the standardization process.
This test suite is used for any tests requiring
`--harmony-shadow-realm` until the proposal is finalized. Once it's
finalized, this test suite can be removed.

See https://github.com/tc39/proposal-shadowrealm/