www-browser is not satisfied by the default Firefox snap

Thank you for your bug report. Do you have the firefox deb installed? It's not providing the software but ensuring the snap is installed and providing www-browser

The Firefox deb is not installed by default (on a minimal or normal install). Installing it manually does fulfill the dependency.
www-browser defaults to wslu if the user did not already install the Firefox deb. This is problematic because the translation packages Ubuntu asks its users to install will pull wslu, and break the desktop, on a fresh install.

The gimp-help-* packages have a dependency on only virtual packages rather than firefox-esr | firefox | chromium | x-www-browser
 or something which is a bug. as it will pick a random one. Also I'm not sure why it would depend on the non-graphical browser virtual package (www-browser) instead of a graphical browser (x-www-browser).

There's no way for repositories to declare the default provider of a virtual package, unfortunately. An approach would be default-x-www-browser | x-www-browser but it's also suboptimal.

There probably should not be a dependency on a virtual package like this, when it contains options that will not actually do what is required of the depency. Wslu is an especially annoying option to have in the list, because it causes all sorts of problems when installed without actually using Windows.

Changing it to graphical browsers only could perhaps be a solution. Although a browser like elinks can be used just fine to read Gimp's help file, getting rid of the problematic wslu as a possible dependency would be worth the loss imo.

Additionally, if relying on the presence of the transitional Firefox deb package is the only way to detect the presence of Firefox snap (when checking dependencies), that Firefox deb package should at least be installed by default, to make sure new users don't run into this problem. A better solution would be to detect the presence of Firefox snap directly, but I don't know if this is technically difficult.

A seperate issue in this case is that, currently, Firefox Snap can't actually open Gimp's help file. It's sandboxing keeps it from accessing local html files not located in /home. Hopefully, this bug will be fixed by Mozilla.

This issue also may affect the default systemsettings in kde:
https://bugs.launchpad.net/ubuntu/+source/systemsettings/+bug/1978842

Note that I am experiencing the same bug in Pop OS 22.04 where Firefox is installed as .deb package (from Pop OS's own apt repositories) and there is no snap.

Anyway, wslu is installed by gimp-help-* and gets the following associations:
* Mime file types: MimeType=x-scheme-handler/http;x-scheme-handler/https;x-scheme-handler/file
* www-browser, via /etc/alternatives/www-browser -> /usr/bin/wslview

I know it's not pure Ubuntu but exactly the same bug in my opinion.

Just found this now, been frustrating me for months. No fix yet? Had to uninstall wslu for now.

This happened to me, and it also changed my default browser for my session. This meant that whenever an application tried to open a link it would just silently fail. I assume I am not the only one with this effect.

Perhaps we need a package which will stay installed which coordinates with the snap somehow.

I had to install konqueror to satisfy www-browser dependency.