From Fedora Project Wiki
Python Version Support
In Fedora we have multiple Python runtimes, one for each supported major Python release. At this point that's one for python3.x and one for python2.x. However the python2 stack will eventually be removed. If a piece of software supports python3, it MUST be packaged for python3. If it supports python2 as well, it SHOULD NOT be packaged for python2 unless there is a specific reason (e.g. because it's a dependency for another package that doesn't support python3 yet). If it supports only python2 then (obviously) it must not be packaged for python3. The packager SHOULD contact upstream and encourage them to correct this mistake.