$ git clone -n https://src.fedoraproject.org/rpms/mate-screensaver.git /var/lib/mock/f42-build-side-1-3499423-45965/root/chroot_tmpdir/scmroot/mate-screensaver
Cloning into '/var/lib/mock/f42-build-side-1-3499423-45965/root/chroot_tmpdir/scmroot/mate-screensaver'...
$ git fetch origin cfe37bcfa5e438ce52b27960845f5130997f8ed5:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mate-screensaver
 * [new ref]         cfe37bcfa5e438ce52b27960845f5130997f8ed5 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at cfe37bc add some upstream commits