For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:weberho:branches:server:php:applications/openSUSE_Tumbleweed/home:weberho:branches:server:php:applications.repo
zypper refresh
zypper install processwire3
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:weberho:branches:server:php:applications/15.5/home:weberho:branches:server:php:applications.repo
zypper refresh
zypper install processwire3
For 15.4 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:weberho:branches:server:php:applications/15.4/home:weberho:branches:server:php:applications.repo
zypper refresh
zypper install processwire3