openSUSE Tumbleweed with KDE Plasma 5.9.3 and plasma5-pk-updates 0.2-7.1 Steps to reproduce: 1. Open the Software Update plasmoid when there are updates available 2. Click on one 3. Hit the up or down arrow key Expected result: The selection should change to the next or previous update, allowing you to see the its update description (if available). Actual result: Nothing happens. The arrow keys do not navigate to the next or previous updates in the list.
I'm afraid this widget is unmaintained and has not been ported to Qt 6, meaning it's no longer released; closing all of its bug reports.