[Wowfunhappy]

Interesting. I'm now doing some more Googling, and I can't seem to find a place that explains why the APSL isn't GPL compatible. (But it's almost certainly not, given that lots of authoritative sources including GNU[1] say as much. They just don't say why.)

1: https://www.gnu.org/philosophy/apsl.en.html

[ghaff]

Probably (I haven't studied it) because of what the FSF says here "It is not a true copyleft, because it allows linking with other files which may be entirely proprietary." So it's apparently file-based copyleft, which is in the same vein as CDDL. (Which is also generally considered GPL-incompatible for that reason.)