Search for "kNotes" in "kRunner". One result is found via Software Center: Software Center > Get KNotes... > Sticky Notes Application Via Konsole run: appstreamcli search knotes And I get: Identifier: org.kde.knotes.desktop [desktop-application]... But using Discover to search for kNotes I get: "Sorry, nothing found..." And more importantly, when I click the KRunner "Get Knotes" item... I get: "Couldn't open appstream://org.kde.knotes.desktop I'm located in China, but I'm using Shadowsocks and have the system proxy configured. Also appstreamcli is working fine.
Do you have packagekit-qt5 installed?
Please answer Antonio's question.
If you can provide the information requested in comment #1, please add it.
You are correct. packagekit-qt5 was not installed. Installation fixed "couldn't open appstream" error and now everything works as expected. Thank you.