This usergroup seems to be unused for years, and I cannot find any indication of what it originally was used for.
Let's remove it, to clean things up.
https://codesearch.wmflabs.org/search/?q=communityapps&i=nope&files=&repos=
https://office.wikimedia.org/w/index.php?title=Special:ListUsers&group=communityapps
(and no useful search results in mw.o, phab, metawiki, or officewiki)