3 – Other wikis pages (Meta, Wikipedias....) (37%)
4 – Mailing lists (63%)
5 – Facebook (7%)
6 – Twitter (11%)
7 – Slack (11%)
8 – GitHub (51%)
9 – Messenger (3%)
From the technical contributors who participated in this question, the four channels that were reported most often for participating in Wikimedia software development were Phabricator (73%), Mediawiki wiki pages (63%), mailing lists (63%), and github (51%).