For openSUSE Leap 15.3 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:alarrosa:packages/openSUSE_Leap_15.3/home:alarrosa:packages.repo
zypper refresh
zypper install dupeguru
For SLE 15 SP4 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:alarrosa:packages/SLE_15_SP4/home:alarrosa:packages.repo
zypper refresh
zypper install dupeguru
For SLE 15 SP3 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:alarrosa:packages/SLE_15_SP3/home:alarrosa:packages.repo
zypper refresh
zypper install dupeguru