So nothing special there. What more info you need?
Please, send the resolver debug output at least, as it might shed some light. Try:
```
-o Debug::pkgProblemResolver=yes
```
Well one might think that if new libglvnd0 is backward incompatible with
xserver in the 'main' there should be new one in the 'backport'. Or
maybe libglvnd0 is 'silently' dependent of such backport package.
Just trying to make sense of obviously bad behavior. An other thought
was whether this has something to do with Wayland.
At any rate, it literally depends on a single package, libc6, therefore it should not remove xserver-org (and I haven't spotted such a peculiarity myself).