[SXX]

I wouldn't argue about this exact file since it's might be a bit more recent, but that game is about 25 years old. Do you seriously think keeping it on archive.org is bad?

It's very likely to not work on modern systems anyway (dosbox will work of course) and version from GOG likely wouldn't be installable on let's say DOS or Windows 95. And there is plenty of people who might want to run old games on some ancient PC for personal fun or for museum-like purposes.

Another option for open source projects it's to just use demo version which is 100% legit way to get assets. Though it's not always possible because some demo versions don't contain whole assets that fully-featured engine would depend on.