Briefly discussed during today's daily: It might be possible to somehow add a type to the <references /> tag to change the heading of all references in a group to "Note". Currently the only possibility to do something like this is <div class="notes"><references /></div>. It's technically not very difficult to teach the individual popups to look for this class name. Another possibility is to reserve group names for this purpose (e.g. group="notes")[1] or add support for class="…" or something similar directly to the <references /> tag. The biggest issue is to come up with a specification:

• It should be easy to do and to understand in the wikitext.
• Ideally not only English but localizable (however, the current types aren't localizable either).
• It should be unlikely a user accidentally triggers this. Note that <references /> tags are very often wrapped in <div> for various reasons. We should pick a class name that is not already used for other purposes.

[1] Note there are already pre-defined group names like group="upper-roman". It would be impossible to use that together with "notes", which is probably not a good idea.

Would note this on the open task instead of the closed one: <cite> HTML tag is used to describe ‘the title of the cited work’, not any citation, so asking for <cite class="note"> is asking for incorrect HTML syntax since notes are usually just comments on something. Maybe this can be salvaged though by also allowing to match any <span class="mw-cite-note">, for example.