For example https://commons.wikimedia.org/wiki/Special:Version lists a parser extension tag `<languages>`, but it's unclear which extension added this tag (until you search mediawiki.org :) ). Likewise the tag `<talkpage>` on mw.org. Someone wrote [[ https://www.mediawiki.org/wiki/Parser_extension_tags | Parser extension tags]] to manually solve this problem but it's out-of-date.
The Parser doesn't easily know who called `setHook()` to add a tag, so this seems hard to do. If extension registration were extended to call `parser->setHook()` based on extension.json information then it would know , but that wouldn't work if an extension needed to register conditionally e.g. in a `ParserFirstCallInit` hook.
(BTW
$ ack-grep --php 'setHook.*languages' includes extensions
reveals that the [[ https://www.mediawiki.org/wiki/Extension:Translate | Translate extension ]], not UniversalLanguageSelector, adds the `<languages>` hook.)