Amendment; it seems the other FUTO product has a 10 purchase. So it's not free, but seems to be winrar's approach. "Please pay, but if you don't we won't know"

Assuming my understanding is correct;

By the spirit of the definition, no.

By the literal definition - yes; it's free and the source is open to look at. You could fork it, but you can't sell your own version.

I have no idea if you could redistribute a modified version freely without breaching the license terms - enforcement is key. The language could be there just to prevent any of the big tech companies from just forking and profiting from the work.

This is purely speculation, and shouldn't be considered fact.