For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:tyrannishawk/openSUSE_Tumbleweed/home:tyrannishawk.repo
zypper refresh
zypper install steam-login-session
For openSUSE Factory ARM run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:tyrannishawk/openSUSE_Factory_ARM/home:tyrannishawk.repo
zypper refresh
zypper install steam-login-session
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:tyrannishawk/15.5/home:tyrannishawk.repo
zypper refresh
zypper install steam-login-session
For 15.4 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:tyrannishawk/15.4/home:tyrannishawk.repo
zypper refresh
zypper install steam-login-session