$ git clone -n https://src.fedoraproject.org/rpms/vdr-screenshot.git /var/lib/mock/f40-build-2719914-73027/root/chroot_tmpdir/scmroot/vdr-screenshot
Cloning into '/var/lib/mock/f40-build-2719914-73027/root/chroot_tmpdir/scmroot/vdr-screenshot'...
$ git fetch origin b1d6fc1fb9d73edc8f7fb0eae03ace2a1ce8722e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/vdr-screenshot
 * [new ref]         b1d6fc1fb9d73edc8f7fb0eae03ace2a1ce8722e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b1d6fc1 Rebuilt for new VDR API version