In order to do T74715: Convert some MW core special pages to OOUI, we need Special:PasswordReset to generate OOUI-enabled HTML. In order to do that, we need to extend HTMLForm to be able to generate OOUI-enabled forms. And in order to do that, we need to disentangle MediaWiki UI "VForms" from HTMLForm code (added in d32891d99f185e5cf2b0e25bf947de221d4c3295), unless, of course, we want to go mad.
This bug is about not going mad.