From Fedora Project Wiki
Macro Normal Definition Notes
__python2 /usr/bin/python2 Python 2 interpreter. Also the default python interpreter
__python3 /usr/bin/python3 Python 3 interpreter
python2_sitelib /usr/lib/python2.X/site-packages Where pure python2 modules are installed
python2_sitearch /usr/lib64/python2.X/site-packages on x86_64
/usr/lib/python2.X/site-packages on x86
Where python2 extension modules that are compiled C are installed
python3_sitelib /usr/lib/python3.X/site-packages Where pure python3 modules are installed
python3_sitearch /usr/lib64/python3.X/site-packages on x86_64
/usr/lib/python3.X/site-packages on x86
Where python3 extension modules that are compiled C are installed
py3dir %{_builddir}/python3-%{name}-%{version}-%{release} Directory to use when building python3 modules from the same source tarball as python2 modules
py_byte_compile (script) Defined in python3-devel. See the [#Bytecompiling_with_the_correct_python_version bytecompiling] section for usage
python3_version 3.X Defined in python3-devel. Useful when running programs with Python version in filename, such as nosetest-%{python3_version}
python3_version_nodots 3X Defined in python3-devel since Fedora 21 / Python 3.4. Useful when listing files explicitly in %files section , such as %{python3_sitelib}/foo/*.cpython-%{python3_version_nodots}.pyo