SUMMARY
Discover will crash when I attempt to search for applications using any search term, or when I try to view installed applications. This began happening at least with Discover 6.0.1, the first version I was able to try since Plasma 6 released (Arch didn't update until Plasma 6.0.1).

When searching, Discover will go to the "Search" page and show the spinner with the text "Still looking..." - After a couple of seconds, the spinner will hang, Discover becomes unresponsive, and a couple of seconds later, it will crash.

This crash also happens in the same way as above, when trying to view the "Installed" page. I don't know that the crashes are the same but the symptoms are the same, which is why I mention it.

Running Discover from the terminal reveals a segfault, but I was unable to trace it down further.
- GDB wanted to download a lot of debug info, and once it exceeded 2GB I aborted.
    - Testing with `unset DEBUGINFOD_URLS; gdb /usr/bin/plasma-discover /path/to/coredump` didn't reveal anything useful as one might expect, since there was no debug information downloaded :-) It basically just told me there was a segfault.
- I could not build Discover locally to debug, likely for reasons unrelated to this issue and more my inexperience building KDE software locally :-)
- Tested in a Gamescope window in case this was display-related but the issue still occurred.
- Tried installing "PackageKit-Qt6" as it was missing (only had PackageKit-Qt5) and no luck.
- I tried disabling all Flatpak sources so that only the PackageKit backend would be used to display system packages.
- I tried backing up and removing my "~/.cache/discover" folder, but this did not resolve the problem.

I tested Discover 6.0.2 on an endeavourOS virtual machine via Boxes (with PackageKit-Qt6 installed to enable to PackageKit backkend), and could not reproduce a crash there. So I suspect this is something specific to my machine - Or, because it crashes on search and viewing installed applications, something specific to an application I have installed.

Since the issue still occurred with the Flatpak backends disabled, perhaps this is specific to the PackageKit backend on my system? Meaning the issue may be coming from an installed package?

The coredump may be too large to attach, I'm also not sure if there is information in it that should not be on a public issue tracker. Having said that, I realise simply saying "Discover crashes but only on this installation" is not too helpful. I am more than happy to do any troubleshooting steps. Perhaps there's a program installed with some behaviour that Discover is not expecting? Maybe a package no longer in some repos or something that one of the Discover backends cannot handle?


STEPS TO REPRODUCE
1. Open Discover
2. Search for an item, or view Installed applications
3. Observe Crash?


OBSERVED RESULT
Discover crashes on search and on viewing installed applications since Discover 6.0.1.


EXPECTED RESULT
Discover should not crash on search or on viewing installed applications (worked on Plasma 5.27.10, last tested version before upgrading to Plasma 6).


SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Linux Zen 6.8.1
KDE Plasma Version: 6.0.2
KDE Frameworks Version: 6.0.0
Qt Version: 6.6.2

ADDITIONAL INFORMATION
I upgraded in-place to Plasma 6, but the endeavourOS VM I was testing on came with Plasma 6 out of the box (the live session iirc was not using Plasma 6, but the installation was using Plasma 6.0.2).