I believe Anthropic has said they won’t publish capabilities research?
OpenAI seems to be sort of doing the same (although no policy AFAIK).
I heard FHI was developing one way back when...
I think MIRI sort of does as well (default to not publishing, IIRC?)
According to Chris Olah:
Doesn’t seem like it’s super public though, unlike aspects of Conjecture’s policy.