Is there a way to find what values are accepted on the RHS of a show rule?

Questions
1

For example, for heading, we at least have:

#show heading: set align(...)
#show heading: set text(...)
#show heading: set block(...)

Other than align(), text(), and block() what other aspects of heading can be customized on the right hand side of its show rule?

Is the only way to find this out at the moment reading Typst’s source code?

Thanks in advance.