Varnishkafka github seems to be obsolete/abandonned. The gerrit repo ( from where it is mirrored from )  link to the wikimedia gitlab.

Sort list.

not sure it deserves its own section, but I didn't really see it fitting in as "Social Media"

 The channel has been around for a few months and has around 20 users (mostly popping up when then need help :-)), and I believe the lower barrier of entry compared to IRC could help adoption.