$ git clone -n https://src.fedoraproject.org/rpms/jansson.git /var/lib/mock/f42-build-863074-171398/root/chroot_tmpdir/scmroot/jansson
Cloning into '/var/lib/mock/f42-build-863074-171398/root/chroot_tmpdir/scmroot/jansson'...
$ git fetch origin be89b7a473331177adf0755a632344caf9af74a2:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/jansson
 * [new ref]         be89b7a473331177adf0755a632344caf9af74a2 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at be89b7a New upstream version 2.14