yast2-squid from YaST:SLE-15:SP3 project
Select Your Operating System
Add repository and install manually
For openSUSE Leap 15.3 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/YaST:SLE-15:SP3/openSUSE_Leap_15.3/YaST:SLE-15:SP3.repo zypper refresh zypper install yast2-squid