I wonder why KiCad 6 doesn't provide a compatibility function for
GetAuxOrigin. The project seems to be trying to reduce the ammount
of code (removing old code) at the cost of breaking every existing
plug-in.
The old mechanism is supported, but removed from examples.
Added a test case for the new mechanism.
Documented the reason for the complex properties.
Added docstrings to these particular cases (with None as default).