14:54
<Domenic>
What wording did TC39 end up with for "icky" features?
15:24
<bakkot>

Domenic:

A conforming implementation of ECMAScript must implement Legacy subclauses, unless they are also marked as Normative Optional. All of the language features and behaviours specified within Legacy subclauses have one or more undesirable characteristics. However, their continued usage in existing applications prevents their removal from this specification. 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.

15:35
<Richard Gibson>

Domenic:

A conforming implementation of ECMAScript must implement Legacy subclauses, unless they are also marked as Normative Optional. All of the language features and behaviours specified within Legacy subclauses have one or more undesirable characteristics. However, their continued usage in existing applications prevents their removal from this specification. 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.

"legacy", as seen at https://tc39.es/ecma262/multipage/fundamental-objects.html#sec-object.prototype.__proto__ and defined at the bottom of https://tc39.es/ecma262/multipage/conformance.html#sec-conformance