My humble opinion is that we can put under the umbrella of the Wikisource Community User Group things that we do as single communities or individuals, for the profit of the whole Wikisource and Wikimedia movement.
For example, things we did this year:
we did the Wikisource Birthday proofreading contests, (which is BIG  :-), and we need to continue doing more and more).
helped Siko in evaluating the IEG proposals related to Wikisource (I did).
are maintaining the migration of WS related tickets from Bugzilla to
Phabricator (thanks Billinghusrt!),
and we are discussing the perennial problem of structured
data on WS (thanks all!)
An I'm not mentioning the hidden but precious work of Phe, Tpt, Ricordisamoa and other coders who maintain the Proofread Extensions, do Wikidata things and more.
So, in the end.
Write whatever we, as a community of wikisourcerors, have done.
Put also important things you havedone in your local wiki. If it's too local, we'll delete it, but it's also a good opportunity to learn stuff from each other!