I've just updated https://meta.wikimedia.org/wiki/Mailing_lists/Overview#Mediawiki_and_technic... . Sorry for the spam, but you may want to skim that and see whether there are lists there you should join. I especially want to single out:

mediawiki-i18n -- localisation and internationalisation wikitech-ambassadors analytics wikitext-l -- the new Visual Editor & parser wikidata-l