After this I was able to pip install -e ".[dev]" as usual and mu is working. Note: I also had to sudo dnf install SDL-devel, but that may be just my (ad-hoc) base system. Nor have I checked the ...
Linux w2l-pc.masua.com 4.15.0-137-generic #141-Ubuntu SMP Fri Feb 19 13:46:27 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux masua@w2l-pc:~/0ai0/SysAdmin$ python Python 2.7. ...