Patch 12.1 has loosened the restrictions that limited the addon to a small handful of private auras. GTFO can now warn you about any mechanic that applies a trackable debuff, including additional warnings when that debuff stacks.
This still doesn’t restore everything GTFO could do before Midnight, but it opens the door to bringing back a lot more alerts. Over the next months, I’ll be testing raids and dungeons and working to restore support in delves, PvP, and outdoor content wherever possible in addition to updating older content.
I’ve posted the full breakdown on CurseForge, but my trust level isn’t high enough to post links on the forums yet.