The thread there also suggests that you should put this in COPR instead, since the experience will be bad with trying to keep things in sync between mutter and gnome-shell.

Additionally, with Fedora 42+, you cannot use X11 sessions by default with GDM and GNOME anyway.

The thread there also suggests that you should put this in COPR instead

Same answer as for Plasma X11 support: just no.

since the experience will be bad with trying to keep things in sync between mutter and gnome-shell.

The package already tries to ensure that dnf will withhold out-of-sync updates:

# Make sure dnf updates gnome-shell together with this package; otherwise we
# might end up with broken gnome-shell installations due to mutter ABI changes.
Conflicts: gnome-shell < 45~rc

Additionally, with Fedora 42+, you cannot use X11 sessions by default with GDM and GNOME anyway.

So a .session file for that should be shipped along with this package, or in a separate small noarch package.

We ship the session files, it doesn't change that GDM does not load them. You have to use a different login manager, and that significantly reduces the desktop's functionality (since you lose the lockscreen if you don't use GDM).

it doesn't change that GDM does not load them.

Why not? So do we need to ship a patched GDM? Or can the unpatched GDM somehow be fooled into not realizing that the session file is for an X11 session and be forced to accept it?

I am fed up of this patronizing of users by GNOME/GTK developers, see also: https://copr.fedorainfracloud.org/coprs/kkofler/gtk-4.18-gles2/

The thread there also suggests that you should put this in COPR instead

This isn't the same considering gnome is dropping X11 support.
Maybe someone will fork gnome again (like cinnamon) to retain X11.

Same answer as for Plasma X11 support: just no.

I see little point in packaging this patched mutter version, it's likely to be broken by newer gnome-shell

$ rpm -q gnome-shell
gnome-shell-48.0-1.fc42.x86_64

It already conflicts with f42+

since the experience will be bad with trying to keep things in sync between mutter and gnome-shell.

The package already tries to ensure that dnf will withhold out-of-sync updates:
```

Make sure dnf updates gnome-shell together with this package; otherwise we

might end up with broken gnome-shell installations due to mutter ABI changes.

Conflicts: gnome-shell < 45~rc
```

It already conflicts with f42+

Here, the patch is already updated for mutter 48:
https://salsa.debian.org/gnome-team/mutter/-/blob/ubuntu/latest/debian/patches/ubuntu/x11-Add-support-for-fractional-scaling-using-Randr.patch?ref_type=heads
I will update it for Fedora 42 as soon as Fedora 42 is out. I use Fedora 41 so I can only test this version.
I don't really see the point of using a COPR, when this package just could be added to Fedora.
It is already a package on arch: https://aur.archlinux.org/packages/mutter-x11-scaling

AUR is like COPR, it's not part of Arch Linux itself.

Touché, but it is also in upstream Ubuntu. Why can't this package just be added to Fedora?

So do we need to ship a patched GDM? Or can the unpatched
GDM somehow be fooled into not realizing that the session file
is for an X11 session and be forced to accept it?

As a Fedora developer, I humbly request you not to add any downstream patch to GDM for X sessions without running them past the folks maintaining GNOME in Fedora.

Soooo X11 is enabled in gdm again and this package also works under Fedora 42