The proper name of the technology is WSL (Windows Subsystem for Linux), and in fact we already have the wsl tag which covers exactly same topic as ubuntu-on-windows and windows-bash.

I think we should make both ubuntu-on-windows and windows-bash synonyms for wsl, with the following reasoning:

• ubuntu-on-windows is an interim/informal term for wsl, it was briefly used by Microsoft when the technology was first presented, but now it looks like Microsoft abandoned this name and settled with WSL
• The same goes for windows-bash, but there's one more important point: the questions tagged windows-bash mostly have nothing to do with the Bash shell itself, they ask how to run this or that Linux program on Windows