Для openSUSE Tumbleweed запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/home:Simmphonie/openSUSE_Tumbleweed/home:Simmphonie.repo
zypper refresh
zypper install darktable
Для openSUSE Slowroll запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/home:Simmphonie/openSUSE_Slowroll/home:Simmphonie.repo
zypper refresh
zypper install darktable
Для 15.6 запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/home:Simmphonie/15.6/home:Simmphonie.repo
zypper refresh
zypper install darktable