$ git clone -n https://src.fedoraproject.org/rpms/exim.git /var/lib/mock/f40-build-2589437-62568/root/chroot_tmpdir/scmroot/exim
Cloning into '/var/lib/mock/f40-build-2589437-62568/root/chroot_tmpdir/scmroot/exim'...
$ git fetch origin a16df24a490ba33a136940dee20e47b9001c200e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/exim
 * [new ref]         a16df24a490ba33a136940dee20e47b9001c200e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a16df24 Fix PCRE2 memory use explosion (Exim bug 3047)