Gimp 3 apparently installs files in /etc/gimp/2.0/ instead of /etc/gimp/3.0/ and the transition from Gimp 2 to Gimp 3 apparently results in mishandled config files:
I: These configurations now belong to the following packages:
gimp-data: /etc/gimp/2.0/controllerrc
gimp-data: /etc/gimp/2.0/gimprc
gimp-data: /etc/gimp/2.0/gtkrc
gimp-data: /etc/gimp/2.0/menurc
gimp-data: /etc/gimp/2.0/sessionrc
gimp-data: /etc/gimp/2.0/templaterc
gimp-data: /etc/gimp/2.0/toolrc
gimp-data: /etc/gimp/2.0/unitrc
grub-ipxe: /etc/grub.d/20_ipxe
I: They were initially installed by the following packages:
gimp-data: /etc/gimp/2.0/controllerrc
gimp-data: /etc/gimp/2.0/gimprc
gimp-data: /etc/gimp/2.0/gtkrc
gimp-data: /etc/gimp/2.0/menurc
gimp-data: /etc/gimp/2.0/sessionrc
gimp-data: /etc/gimp/2.0/templaterc
gimp-data: /etc/gimp/2.0/toolrc
gimp-data: /etc/gimp/2.0/unitrc
I: Filing bug reports against all packages involved might be a good idea.
The above was found as follow:
ORPHANS=$(dpkg-query --show --showformat='${Conffiles}\n' | grep obsolete | awk '{print $1}')
case $ORPHANS in
"")
echo "I: No obsolete configuration found."
;;
*)
echo "I: These configurations now belong to the following packages:"
dpkg-query --search $ORPHANS | sort
echo "I: They were initially installed by the following packages:"
dpkg-query --show --showformat='${Package}\n${Conffiles}\n' | awk '/^[^ ]/{pkg=$1}/ obsolete$/{print pkg":",$1}' | sort
echo "I: Filing bug reports against all packages involved might be a good idea."
;;
esac