$ git clone -n https://src.fedoraproject.org/rpms/sane-backends.git /var/lib/mock/f40-build-2041089-48407/root/chroot_tmpdir/scmroot/sane-backends
Cloning into '/var/lib/mock/f40-build-2041089-48407/root/chroot_tmpdir/scmroot/sane-backends'...
$ git fetch origin 34e7ef5c253d9fa614c361decc7c004cad12b3ba:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/sane-backends
 * [new ref]         34e7ef5c253d9fa614c361decc7c004cad12b3ba -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 34e7ef5 Fix building against libxml2 2.12.0