$ git clone -n https://src.fedoraproject.org/rpms/cosmic-session.git /var/lib/mock/f41-build-side-1-3102172-39352/root/chroot_tmpdir/scmroot/cosmic-session
Cloning into '/var/lib/mock/f41-build-side-1-3102172-39352/root/chroot_tmpdir/scmroot/cosmic-session'...
$ git fetch origin e3c666562755053d84d45b82f536595416f68a7e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/cosmic-session
 * [new ref]         e3c666562755053d84d45b82f536595416f68a7e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e3c6665 Require system-cosmic-config