https://bugzilla.redhat.com/show_bug.cgi?id=823096
--- Comment #4 from Adam Jackson ajax@redhat.com --- (In reply to comment #3)
Thanks for noticing it.
A grep -ri s3tc shows only references to it in src/nvtt/squish/texture_compression_s3tc.txt
Simply searching for s3tc is not enough. There are multiple variants of S3TC, named DXT[1-5]. Which I definitely see code for in here. I don't think this is something Fedora can ship.