$ git clone -n https://src.fedoraproject.org/rpms/gnome-system-monitor.git /var/lib/mock/f42-build-3426658-45197/root/chroot_tmpdir/scmroot/gnome-system-monitor
Cloning into '/var/lib/mock/f42-build-3426658-45197/root/chroot_tmpdir/scmroot/gnome-system-monitor'...
$ git fetch origin 223d63413b6054c6a9a10bdb7e5b6e8a0857b265:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gnome-system-monitor
 * [new ref]         223d63413b6054c6a9a10bdb7e5b6e8a0857b265 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 223d634 Update to 48.0