On my Rawhide machine, after updating, modprobe xfs is needed in order to mount XFS filesystems.
I can’t remember what component is responsible these days for automatically loading modules (udev?), so I don’t know where to look for what’s the problem. Any ideas?
Well there you go, after finding the right search, I come across my own article from more than a decade ago … How does mount load the right kernel module? | Richard WM Jones
And the reason is because the symlink from /sbin/modprobe to /bin/modprobe wasn’t set up, probably because this appliance I’m using doesn’t run the filesystem.spec script. Ho hum.
Interesting case, if you investigate this deeper feel free to keep us updated. I’d be interested how this occurred, and in what conditions. But this would be more out of curiosity rather than for professional reasons, so don’t feel pressured 
Regards from the Stateofopencon at St.Pauls 
The RPM appliance installer I’m using doesn’t run RPM scripts, hence if doesn’t run the rather convoluted script in filesystem.spec, hence the symlink wasn’t set up.
I never would have expected that this task is done through filesystem.spec or a spec file at all, but I am obviously not an expert about this. Thanks for the elaboration!