$ git clone -n https://src.fedoraproject.org/rpms/fbg2.git /var/lib/mock/f41-build-756362-13418/root/chroot_tmpdir/scmroot/fbg2
Cloning into '/var/lib/mock/f41-build-756362-13418/root/chroot_tmpdir/scmroot/fbg2'...
$ git fetch origin f4ddfe9ca211fb76296f97f9961caa35a2186110:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/fbg2
 * [new ref]         f4ddfe9ca211fb76296f97f9961caa35a2186110 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at f4ddfe9 Eliminate use of obsolete %patchN syntax (#2283636)