$ git clone -n https://src.fedoraproject.org/rpms/mailnag.git /var/lib/mock/f41-build-750929-13388/root/chroot_tmpdir/scmroot/mailnag
Cloning into '/var/lib/mock/f41-build-750929-13388/root/chroot_tmpdir/scmroot/mailnag'...
$ git fetch origin 552d30ec8dc34aa7d5b11e61a77fd57d15fc0a90:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mailnag
 * [new ref]         552d30ec8dc34aa7d5b11e61a77fd57d15fc0a90 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 552d30e Eliminate use of obsolete %patchN syntax (#2283636)