Detailed explainations about tmTheme?

Question

The core theme system of VS Code is from TextMate (https://macromates.com/manual/en/themes)

This system is also used in Sublime text (https://www.sublimetext.com/docs/color_schemes_tmtheme.html)

I searched a lot about the tmTheme rules, but still confused about those details. For example I have below pPython code:

import typing

class MyClass:
  def __init__(self, age: typing.Optional[int] = None) -> None:
    self.age = age


mine = MyClass(10)

In this example code, I am confused over what entity.name.class and variable.other.constant are, so I'm not sure what color I should use when I try to create/customize my theme.

Are there any detailed docs about tmTheme?