Nobody mentionned it (yet), but I'll add a few words about macOS. I have been in contact with two persons who respectively:
- used the Windows version sucessfully with a recent version of Wine on an Intel-based Mac (it failed with an older version of Wine) - built it from source on an ARM-based Mac. It seemed to work fine (and fast!) with the exception of the tutor mode that hanged. As far as I know there is no work on an independently installable version for macOS, but the second example above suggests that it should not be too difficult for someone familiar with these repositories to add an at least mostly functional gnubg to Homebrew or Macports.
