For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:dl8fcl:sdr/openSUSE_Tumbleweed/home:dl8fcl:sdr.repo
zypper refresh
zypper install osmosdr
For 15.6 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:dl8fcl:sdr/15.6/home:dl8fcl:sdr.repo
zypper refresh
zypper install osmosdr
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:dl8fcl:sdr/15.5/home:dl8fcl:sdr.repo
zypper refresh
zypper install osmosdr