What type of documentation are you looking for? The big picture is easily googleable and wikipediable: EY got a few of the super-rich excited enough about doomer drama to bankroll the founding of OpenAI, whose governing body was mostly EAs (until the Altman-Nadella counter-coup) while Anthropic were the people who bailed because they though OAI weren't serious enough about alignment, and suddenly getting dicked in a rationalist compound group house has immense career implications in the burgeoning AI sector.

Also terms like AGI, ASI, AI alignment, existential risk et al started out as lesswrong shibboleths, and so-called alignment research is almost completely a rationalist circlejerk.

Pinning the EA/rats down as a cult is where it gets murkier because it's mostly them telling on themselves in social media and blog post implications, like how they foster a culture of zero personal boundaries, ingroup overdependence and rigid hierarchies stratified around claimed IQ and proximity to the Great Work of not messing up the robot god incantation that ends the world.

You could do worse than the Behind the Bastards episode on the Zizians, mostly because unlike Leverage or MAPLE who kind of did their own thing but with rationalist funding and human capital, the Zizians can be fairly described as what happens if you actually take the more esoteric aspects of rationalism seriously.