For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:ka/openSUSE_Tumbleweed/home:ka.repo
zypper refresh
zypper install liferea
For openSUSE Slowroll run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:ka/openSUSE_Slowroll/home:ka.repo
zypper refresh
zypper install liferea
For 16.0 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:ka/16.0/home:ka.repo
zypper refresh
zypper install liferea