What sub-apis are available on auth0 inside of a rule?

Looking at the example for verification emails at: Customize Email Handling

there is a call to a method of the auth0.users object.

Is auth0 and authenticated ManagementAPI instance? If so, what other managers are hanging off it? By experimentation, the TicketsManager does not appear to be there… what is?

Please see this document which explains in more detail: