For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:iDesmI:kf6/openSUSE_Tumbleweed/home:iDesmI:kf6.repo
zypper refresh
zypper install signon
For openSUSE Slowroll run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:iDesmI:kf6/openSUSE_Slowroll/home:iDesmI:kf6.repo
zypper refresh
zypper install signon
For KDE Frameworks run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:iDesmI:kf6/KDE_Frameworks/home:iDesmI:kf6.repo
zypper refresh
zypper install signon