Netsurf is under the GPL, licensing is only problematic if your trying to sell the derivate work without giving back the changes and providing the source code on request.
For example including the software in a binary only package, distribution, or included with physical hardware that you are selling for profit and not providing the source code through some other means.
Im fairly sure the 68k Netsurf fork is playing by the rules.
That its not very frequently updated is far from surprising though.