The [[https://www.mediawiki.org/wiki/ResourceLoader/Modules#jQuery.makeCollapsible|mw:RL/DM#jQuery.makeCollapsible]] plugin available since MediaWiki 1.18 is supposed to be used as a replacement for the old NavFrame and Collapsible[2] tables which is still to be copied from one [[https://en.wikipedia.org/wiki/MediaWiki:Common.js|MediaWiki:Common.js]] to other all over Wikimedia wikis, being frequently outdated on small projects[3]. Nonetheless, it (apparently) still doesn't support the 'autocollapse', 'innercollapse' and 'outercollapse' options which are available on the current scripts (see [[https://en.wikipedia.org/wiki/Help:Collapsing|Help:Collapsing]]). And we want {T71550}, not to **duplicate** code for the same functionality and send **both** versions for the visitors by default.
These options are essential in order to update the existing templates, such as [[https://en.wikipedia.org/wiki/Template:Navbox|Template:Navbox]], [[https://en.wikipedia.org/wiki/Template:Americanfootballbox|Template:Americanfootballbox]], [[https://pt.wikipedia.org/wiki/Predefini%C3%A7%C3%A3o:Bloco_de_navega%C3%A7%C3%A3o|pt:Template:Bloco de navegação]], etc, so that we can get rid of the deprecated code (and not send three versions of the code - NavFrame, Collapsible tables and makeCollapsible - for all readers of the wikis).
[1] [[https://en.wikipedia.org/wiki/Wikipedia:NavFrame|Wikipedia:NavFrame]]
[2] [[https://en.wikipedia.org/wiki/Help:Collapsing|Help:Collapsing]]
[3] E.g.: https://pt.wikipedia.org/w/index.php?diff=26477632&oldid=26477354