$ git clone -n https://src.fedoraproject.org/rpms/rust-gobject-sys0.19.git /var/lib/mock/f42-build-side-1-3584796-46896/root/chroot_tmpdir/scmroot/rust-gobject-sys0.19
Cloning into '/var/lib/mock/f42-build-side-1-3584796-46896/root/chroot_tmpdir/scmroot/rust-gobject-sys0.19'...
$ git fetch origin 492062e26ca020fc09298f542c89abd3fadf6505:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-gobject-sys0.19
 * [new ref]         492062e26ca020fc09298f542c89abd3fadf6505 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 492062e compat package no longer needed