Once I figured out where to find the built-in functions, I haven't had a problem finding things since.

Docs > Library Reference > Built-In Functions (browser search for function)

I appreciate that they include all of the built-in functions in the same root directory as the remaining batteries-included modules.

The only wonky one for me now is the documentation for formatting strings, since it's documented in the "strings" module, but it's not dependent on the strings module.