Para Tumbleweed execute o seguinte como root:
zypper addrepo https://download.opensuse.org/repositories/home:plater:lilypond/Tumbleweed/home:plater:lilypond.repo
zypper refresh
zypper install liblo
Para 15.6 execute o seguinte como root:
zypper addrepo https://download.opensuse.org/repositories/home:plater:lilypond/15.6/home:plater:lilypond.repo
zypper refresh
zypper install liblo
Para 15.5 execute o seguinte como root:
zypper addrepo https://download.opensuse.org/repositories/home:plater:lilypond/15.5/home:plater:lilypond.repo
zypper refresh
zypper install liblo