$ git clone -n https://src.fedoraproject.org/rpms/cups.git /var/lib/mock/f42-build-side-1-3501724-45976/root/chroot_tmpdir/scmroot/cups
Cloning into '/var/lib/mock/f42-build-side-1-3501724-45976/root/chroot_tmpdir/scmroot/cups'...
$ git fetch origin f815aa37a048d713e8f4d5718d60f64cd48f3f88:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/cups
 * [new ref]         f815aa37a048d713e8f4d5718d60f64cd48f3f88 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at f815aa3 Fixed memory leak in cupsdAcceptClient