According to this post: http://forums.kronosaur.com/viewtopic.php?f=2&t=4294&start=0#p39977, republic and similar alignments (uplifter, seeker, and constructive chaos) are friendly towards federation (and archivist, hermit, and constructive order), but not vice versa.

nms 20 Jul 2018:

Since making them mutually friendly would result in there being no difference between them whatsoever, this makes them mutually neutral:
https://github.com/kronosaur/Mammoth/pull/57/commits/0a0d70e970a494babb09956817038afb9fc24937

george moromisato 24 Jul 2018:

I agree with @NMS's change and I've merged the PR.