wesnoth from home:fos:branches:openSUSE:Backports:SLE-15-SP4 project
Select Your Operating System
Add repository and install manually
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:fos:branches:openSUSE:Backports:SLE-15-SP4/15.5/home:fos:branches:openSUSE:Backports:SLE-15-SP4.repo zypper refresh zypper install wesnoth