For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:munix9:test/openSUSE_Tumbleweed/home:munix9:test.repo
zypper refresh
zypper install SDL_GameControllerDB
For 15.6 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:munix9:test/15.6/home:munix9:test.repo
zypper refresh
zypper install SDL_GameControllerDB
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:munix9:test/15.5/home:munix9:test.repo
zypper refresh
zypper install SDL_GameControllerDB