Comment 8 for bug 121734

This is not actually a legal problem, although it may be a practical problem. To appreciate why, it's necessary to think about exactly what it means for something to be multiply-licensed.

It means two things:

1) Anyone distributing any of the code must obey at least one of the sets of terms applicable to it

2) Anyone receiving any of the code may use it under any of the terms applicable to each part

The Mozilla Project distributes the source tarballs (case 1) under MPL terms.

The Debian project takes those tarballs (case 2), and wishes to use a subset of the code/data therein under the GPL. That's absolutely fine, because all of the code they want to use is available under GPL terms too. However, in this case it happens to mean that the tarballs are not redistributable under those terms unmodified.

One solution, therefore, seems to be for Debian to modify the tarball before distributing it. However, perhaps this is a practical problem for Debian. Is it?

One further point: some of the files in the remove.nonfree script are in fact in the preferred form for modification. Examples:
rm -fv ./extensions/universalchardet/doc/UniversalCharsetDetection.doc
rm -fv ./xpinstall/wizard/os2/setuprsc/box_ch_d.bmp
rm -fv ./embedding/minimo/mozconfig
I'm fairly sure .rsrc are in the preferred form for modification as well, even though they are binary. If not, what are they compiled from?