Comment by palata
My experience is that people tend to think "permissive = good, copyleft = baaad" as a first approximation. And then "copyleft = GPLv3".
But there are copyleft licenses that are not viral at all and just force the users to distribute their changes to your library, e.g. MPLv2 and EUPL.
I don't understand why one would use a permissive license versus MPLv2 or EUPL.
MPLv2 and EUPL are actually underrated and freedom-promoting for both developer and users. The true successors to the GPLv2 with loopholes closed.
GPL3 gave copyleft a bad name and everyone decided to give away their labour for free.
MPL/EUPL are the spirit of "you can use it, if you spend half a million writing a completely separate module of course you can keep it for yourself, but if you change the actual source files that everybody uses you have to share, so everyone benefits."
Using Linux as example it means one could write their own proprietary driver for their proprietary device, but optimize, say, the memory allocator, please share it so we all benefit.