How about Appendix B? https://tc39.es/ecma262/2024/multipage/additional-ecmascript-features-for-web-browsers.html https://tc39.es/ecma262/2024/multipage/additio

How about Appendix B? https://tc39.es/ecma262/2024/multipage/additional-ecmascript-features-for-web-browsers.html https://tc39.es/ecma262/2024/multipage/additional-ecmascript... > These features are not considered part of the core ECMAScript language. Programmers should not use or assume the existence of these features and behaviours when writing new ECMAScript code. ECMAScript implementations are discouraged from implementing these features unless the implementation is part of a web browser or is required to run the same legacy ECMAScript code that web browsers encounter. Some of these are legacy APIs, but some of them are just plain syntax errors.