Python 3.9 for bullseye
Python 3.9 as a supported Python3 version is now in unstable, and all binNMUs
are done (thanks to Graham for the work). Bug reports should be all filed for
all known problems , and the current state of the 3.9 addition can be seen at
 (a few of the "bad" are false packages with b-d n python3-all-dev, but not
building for 3.9, bug reports also filed).
The major outstanding issue is the pandas stack, all other problems are found in
leaf packages (leaf in the sense of that no other package for the 3.9 addition
Please help fixing the remaining issues!