Add repository and install manually
For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/Virtualization/openSUSE_Tumbleweed/Virtualization.repo zypper refresh zypper install qemu-guest-agent
For 15.6 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/Virtualization/15.6/Virtualization.repo zypper refresh zypper install qemu-guest-agent
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/Virtualization/15.5/Virtualization.repo zypper refresh zypper install qemu-guest-agent