$ git clone -n https://src.fedoraproject.org/rpms/vdr-screenshot.git /var/lib/mock/f40-build-1922759-25101/root/chroot_tmpdir/scmroot/vdr-screenshot
Cloning into '/var/lib/mock/f40-build-1922759-25101/root/chroot_tmpdir/scmroot/vdr-screenshot'...
$ git fetch origin 8076ff74c4bf9a0a3b7e3d1ba8e226ad8361f0ec:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/vdr-screenshot
 * [new ref]         8076ff74c4bf9a0a3b7e3d1ba8e226ad8361f0ec -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8076ff7 Merge branch 'rawhide' into f40