After installing the VM and the corresponding extension (link in discover), the following error message appears immediately. A new machine cannot be created: No default hypervisor could be detected. Ensure that the appropriate QEMU/KVM virtualization and libvirt packages are installed to manage virtualization on this host. A virtualization connection can be added manually via File->Add Connection. SUMMARY Virtual Machine Manager cannot be used. STEPS TO REPRODUCE 1. Installing VM true discover 2. Installing extensions true link in discover 3. Start VM 4. Error OBSERVED RESULT VM errormessage EXPECTED RESULT It should be possible to create a new machine. SOFTWARE/OS VERSIONS KDE Linux 10.02.26 KDE Plasma Version: 6.7 KDE Frameworks Version: 6.24.0 Qt Version: 6.10.2 ADDITIONAL INFORMATION
*** Bug 515807 has been marked as a duplicate of this bug. ***
https://community.kde.org/KDE_Linux#Get_involved To report issues in the KDE Linux operating system itself (i.e. OS design, integration, system services, etc), use invent.kde.org, and ignore the scary red banner at the top of the page. Your bug however is with the virt-manager flatpak from flathub and needs reporting there.
I installed the Virtual Machine Manager directly from Discover. That's why I assumed that the message about “bugs” must be running.