Для openSUSE Tumbleweed запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/Education/openSUSE_Tumbleweed/Education.repo
zypper refresh
zypper install labplot-kf5
Для openSUSE Slowroll запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/Education/openSUSE_Slowroll/Education.repo
zypper refresh
zypper install labplot-kf5
Для 15.6 запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/Education/15.6/Education.repo
zypper refresh
zypper install labplot-kf5