The list of PHP Widgets is not updated since OOUI v0.25.0
Link:- https://www.mediawiki.org/wiki/OOUI/Using_OOUI_in_MediaWiki#List_of_available_elements
The list of PHP Widgets is not updated since OOUI v0.25.0
Link:- https://www.mediawiki.org/wiki/OOUI/Using_OOUI_in_MediaWiki#List_of_available_elements
@Eisheeta I am already started working on that. See New Developers for other contributors.