@EdBoatConnoisseur I'm not sure, but GNU does not allow proprietary versions of gcc and at that time, if you wanted to publish or sell a modified version, you needed to license it under the GPLv2-or-later or GPLv2-only and if you wanted your changes incorporated into the main release, you needed to assign your copyright to the FSF.

The FSF didn't and still won't hesitate to sue if someone was to make a proprietary version of GCC and sell proprietary "licenses" for it.


There was also another case where the "open group" added support for objective C and wanted to release the front end as proprietary software in only object code form, with the user linking it with the back end - but rms said that it wasn't allowed and such proprietary group decided to release that as free software, rather than to throw it all away.