Is this an Annex B only test?

https://github.com/tc39/test262/blob/93d63969bccbf8b4471b7c7fadc875099b7668d3/test/language/literals/regexp/S7.8.5_A1.4_T2.js#L4

It constructed a RegExp like this: new RegExp('\\' + String.fromCodePoint(8204))

It parsed as IdentityEscape. In the main spec it is [~UnicodeMode] SourceCharacter but not UnicodeIDContinue, (btw 8204 is a UnicodeIDContinue), but in annex B it is

[~NamedCaptureGroups] SourceCharacter but not c
[+NamedCaptureGroups] SourceCharacter but not one of c or k