I found an ancient non-versioned API for managing Password Policies. It’s documented on Compass here: passwordPolicy REST API - Compass
It appears that nobody in the history of the Internet has ever used it in publicly available code, nor are there examples on Compass of valid inputs. (Turns out it accepts form data as imports, not JSON, which was fun to figure out, since it outputs JSON.)
Are there plans to create a v3 or beta API for password policies? If not, why not?