sle15_python_module_pythons

I see more and more %{?sle15_python_module_pythons} and %{sle15modernpython} in packages changes. But i can't find any documentation about it. Not in wiki and not in python-rpm-macro. So what's the deal with "%{?sle15_python_module_pythons}" ? And what's the deal with "%{sle15modernpython}" ? Regards Eric