cosmic-ext-applet-clipboard-manager from X11:COSMIC:Backports project
Sty agraw n unessmres nnek/m
Add repository and install manually
For 15.6 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/X11:COSMIC:Backports/15.6/X11:COSMIC:Backports.repo zypper refresh zypper install cosmic-ext-applet-clipboard-manager