Center For Applied Rationality. They hosted "workshops" were people could learn to be more rational. Except there methods weren't really tested. And pretty culty. And reaching the correct conclusions (on topics such as AI doom) were treated as proof of rationality.
Edit: still host, present tense. I had misremembered some news of some other rationality adjacent institution as them shutting down, nope, they are still going strong, offering regular 4 day ~~brainwashing sessions~~ workshops.
Mesa-optimization? I'm not sure who in the lesswrong sphere coined it... but yeah, it's one of their "technical" terms that don't actually have academic publishing behind it, so jargon.
Instrumental convergence.... I think Bostrom coined that one?
The AI alignment forum has a claimed origin here is anyone on the article here from CFAR?