I wrote:
You need to find out why the license was considered non-Free by
Fedora.
Whatever requirement caused that determination is almost certainly also
incompatible with the GPL. I am no lawyer and I can't find the offending
requirement at first glance, but that doesn't mean it doesn't exist.
PS: Oh, and even if the license were free, chances are it'd still be
incompatible with the GPL due to wording differences. I think an exception
is unavoidable unless OpenCASCADE upstream (and if you use the community
edition, also every single contributor to that fork) relicenses their code
to the GPL or a GPL-compatible license. (Note that every single contributor
to FreeCAD needs to agree to the exception. Yes, licenses are a PITA.)
Kevin Kofler