gnome-shell-extension-user-theme from home:alexandrite-os project
Select Your Operating System
Add repository and install manually
For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:alexandrite-os/openSUSE_Tumbleweed/home:alexandrite-os.repo zypper refresh zypper install gnome-shell-extension-user-theme