Для openSUSE Tumbleweed запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/games:tools/openSUSE_Tumbleweed/games:tools.repo
zypper refresh
zypper install mangohud
Для 15.6 запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/games:tools/15.6/games:tools.repo
zypper refresh
zypper install mangohud
Для 15.5 запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/games:tools/15.5/games:tools.repo
zypper refresh
zypper install mangohud