$ git clone -n https://src.fedoraproject.org/rpms/plasma-bigscreen.git /var/lib/mock/f40-build-2255746-54263/root/chroot_tmpdir/scmroot/plasma-bigscreen
Cloning into '/var/lib/mock/f40-build-2255746-54263/root/chroot_tmpdir/scmroot/plasma-bigscreen'...
$ git fetch origin 2427ba394adacda78c350cb6fca39ae1d8ea1592:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/plasma-bigscreen
 * [new ref]         2427ba394adacda78c350cb6fca39ae1d8ea1592 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 2427ba3 5.27.9