Docs
The public data and feeds, which need no key, and the account endpoints, which do.
Suggesting a service, what moderators and the bot do with it, and correcting a listing.
Login keys, what an account holds, and how to delete one.
Show a service's KYC level on another site, in a frame that runs no script.
How scores are worked out is on About & method, and what karma does on How karma works.