In November 2018, Meta Stack Exchange received its first set of community moderators since the Meta Stack Overflow-Meta Stack Exchange split (which saw this site being renamed from the former to the latter, and a new per-site meta being established for Stack Overflow).
Prior to that, all moderators of the Trilogy sites (Stack Overflow, Server Fault, and Super User) were moderators of this site, in addition to SE staff.
After some research (and my noticing some old "moderator" actions on deleted posts by people who were never Trilogy moderators or Stack Exchange staff), I noticed that this site had a set of four moderators who exclusively moderated this site (rather than being a staff member or a Trilogy moderator). Two of them were appointed as a result of their past activity on the UserVoice site that preceded this site (Joel Coehoorn and EndangeredMassa), and the other two (Kyle Cronin and Tom Ritter) were brought in as they had created external "meta" sites.
What happened to these four moderators? Did they all retire? Were their privileges revoked once the split happened? Were they removed for inactivity?