Discover does not show APT Repos

[My1xT]

Hello,
I have the issue that one one of my 2 Machines (Both have Kubuntu 24.04, upgraded from 22.04, yet on one of them discover doesnt seem to list any APT Repos, which is kinda annoying for management, for the other one it seems to work tho. The Discover Version is 5.27.12 for both of them.

[claydoh]

I will bet one machine is an upgrade, the other a fresh installation?

This is a known issue. Debian's apt has a new source file format, and Ubuntu started using it in either 23.10 or 24.04.
Plasma's apt backend. or packagekit, or both, don't like the new format, and it still hasn't been fixed.

It has been mentioned a few times here.
A workaround is to replace the new file /etc/apt/sources.list.d/ubuntu.sources with the old style /etc/apt/sources.list, as well as doing something simillar for any PPAs and other wexternal repos.
Notice that this also breaks the button in Discover for the Software Sources tool,

Another more logical workaround is to get to the Software Sources tool manually (sudo software-properties-qt), or by going to the Driver Manager in System Settings. That entry simply opens the Software Sources tool focused on the drivers tab there.