________________________________________
> Although I could add files to mirror.ppa.trinitydesktop.org in the same
> way, they would be removed at the next regular update from the François
> source :)

Understood!

The trinity-tdm package problem seems to be related to SElinux:
https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fbugzilla.redhat.com%2Fshow_bug.cgi%3Fid%3D746073&data=02%7C01%7Cplaws%40ou.edu%7C7513702337d74c2e264108d73d2a000e%7C9c7de09d903444c1b462c464fece204a%7C1%7C0%7C637045122921641678&sdata=cqJTbQ9zUhGto0hYwVj4Vqyq5aYzBqF4RePfyUKQ9Lo%3D&reserved=0


Good clue!  Did the usual sealert/ausearch/audit2allow/semodule (after telling yum to grab the rpm for me and running the -Uvvh ...) and now all appears well.  

Wish me luck that Nvidia doesn't kill me on the reboot!  :-D

THANK YOU, Slavek!