libyui from devel:libraries:libyui:SLE-15:SP6 project
Select Your Operating System
Add repository and install manually
For 15.6 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/devel:libraries:libyui:SLE-15:SP6/15.6/devel:libraries:libyui:SLE-15:SP6.repo zypper refresh zypper install libyui