We still have stuff running on a legacy mainframe and/or DOS… Over time more and more gets migrated away from that system, but our warranty/reliability team still have to deal with that system (because all of our historical warranty/reliability data is still there)
I’m currently typing this from a Win10 19xx build, and that’s only because I’m an “early tester”. Most of the company is still on Win10 1803. I’m one of two people to have migrated to Ubuntu 20.04 for our Linux machines, and it’s been majorly problematic (because GnuTLS seems to have inferior regression testing compared to OpenSSL, with the end result being that there are regressions that break in weird ways when going through a Fortigate proxy.)
As to SCM systems - some have ditched Github because they don’t like the fact that Microsoft purchased them, and still treat Microsoft post-Nadella as being the same company ran by Gates or Ballmer (it’s pretty clearly not…), but I think github, gitlab, or bitbucket would work fine. I think github is dominant/most common so you’ll likely see a bit more contributor activity there if you don’t have some specific objection to it. Sourceforge is definitely problematic after the drive-by-download/spyware incidents a few years ago as a result of their new ownership. I tend to assume any project still on SF is dead…
I have done C bindings of Python before, but not for a LONG time. I’m rusty as hell, but maybe can take a look at it once the “latest and greatest” code is somewhere.