Switch from snap to apt for reinstalling GIMP 2.10.30
sudo apt update and sudo apt install gimp-help-common gimp-help-en
Update the installed version of Firefox from 113 to 114.
Here's how I got there:
I was unable to display the help pages of GIMP 2.10.30, online as well as locally, on my laptop with Ubuntu 22.04. I had installed GIMP 2.10.30 via Ubuntu Software.
When I uninstalled the snap version of GIMP (from Ubuntu Software), and installed GIMP via the command sudo apt install gimp I was able to view the help pages online (after reading How do I open the user manual in GIMP?).
And the solution for the locally stored help pages came eventually today, when I updated Firefox 113 to Firefox 114, both snap packages from Ubuntu Software.
To install the help pages locally I typed following commands:
sudo apt update
sudo apt install gimp-help-common gimp-help-en
which I found by reading Cannot access GIMP help because AppArmor stops it.
(If I remember well, in the snap version of GIMP the message that the manual wasn't locally installed was displayed after the two commands above (in Edit -> Preferences -> Help System) , but this changed when I uninstalled the snap version of GIMP and installed the apt version.)
The help pages were locally stored in the directory /usr/share/gimp/2.0/help/en. At first I wasn't aware that Firefox opens my locally stored html-pages by default. Firefox 113 was unable to display the files when I tried to open them via GIMP and via nautilus (it only displayed the pages when I searched for it in the Firefox browser by pressing ctrl+o). Firefox's update to 114 of 6/6/2023 solved the issue.
