After the rebase onto mutter 3.36.0-0ubuntu0.20.04.1, there are mentions of mutter remaining in the CLI interface

[audibleptr]

After the 8599127 rebase, there are now at least a few mentions of mutter remaining in the CLI interface (see e.g. the https://github.com/linuxmint/muffin/blame/94a950abd1f853d1f0d0ca5d2133c58befc6b363/src/core/mutter.c#L38 file).

For instance, mutter 5.8.0 in:

$ muffin --version
mutter 5.8.0
Copyright © 2001-2011 Havoc Pennington, Red Hat, Inc., and others
This is free software; see the source for copying conditions.
There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

And, more importantly, the CLI argument --mutter-plugin=PLUGIN Mutter plugin to use also changed its name in:

$ muffin --help
Usage:
  muffin [OPTION?]

Help Options:
  -h, --help                 Show help options

Application Options:
  --sm-disable               Disable connection to session manager
  -r, --replace              Replace the running window manager
  --sm-client-id=ID          Specify session management ID
  -d, --display=DISPLAY      X Display to use
  --sm-save-file=FILE        Initialize session from savefile
  --sync                     Make X calls synchronous
  --x11                      Run with X11 backend
  --version                  Print version
  --mutter-plugin=PLUGIN     Mutter plugin to use

This doesn't cause any issue in usage per se, but not sure whether this was an intended change in muffin 5.4.0 (persisting until the current version in master @ 94a950a).