$ git clone -n https://src.fedoraproject.org/rpms/rust-librsvg.git /var/lib/mock/f42-build-side-1-3581423-46829/root/chroot_tmpdir/scmroot/rust-librsvg
Cloning into '/var/lib/mock/f42-build-side-1-3581423-46829/root/chroot_tmpdir/scmroot/rust-librsvg'...
$ git fetch origin 79c73208f1ef3df6004f409b9daf594899ef36d8:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-librsvg
 * [new ref]         79c73208f1ef3df6004f409b9daf594899ef36d8 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 79c7320 Prevent a temp file left in place by upstream from being packaged