I am currently trying to fix up the palemoon package I’ve had 98% completed at some point in the last year.
(includes uemacs, linux mainline, and others) which simply provides you with instructions to build it locally from source is no legal problem.
There are some questionable inclusions I’ll patch out later in an modified version of Pale Moon. (edit 2017-12-16: this might or might not happen for a very long time)
I should probably give it up (I already had given it up) because of this license, but I’m curious about getting it finished just for the spite of it.