Bug 497963

This is an issue with Linux distributions that ship with fuse3 instead of fuse2. For example, Ubuntu 24.04. If the Krita appimage is executed on such a system, it will fail with the message:

dlopen(): error loading libfuse.so.2

AppImages require FUSE to run.
You might still be able to extract the contents of this AppImage
if you run it with the --appimage-extract option.
See https://github.com/AppImage/AppImageKit/wiki/FUSE
for more information

However, I would consider this a bug for two reasons:

1. FUSE is already installed, just not the version Krita needs
2. For less experienced users, this is completely opaque and the symptom is "Krita doesn't run".
3. If the appimage is executed from the Desktop, there's zero indication what's wrong, the app just does not run.

See this tread for an example: 
https://krita-artists.org/t/can-not-install-krita-on-ubuntu/110345

It seems AppImage can be built in a way that does not depend on runtime dependency. I found this issue addressing this problem:
https://github.com/AppImage/AppImageKit/issues/1120

Ideally, the AppImage should be compatible with old and new distros that use either version of FUSE.