$ git clone -n https://src.fedoraproject.org/rpms/libesmtp.git /var/lib/mock/f41-build-750602-13382/root/chroot_tmpdir/scmroot/libesmtp
Cloning into '/var/lib/mock/f41-build-750602-13382/root/chroot_tmpdir/scmroot/libesmtp'...
$ git fetch origin 908ea1d86f1ad9fe3bb8affe8c42f657b5f3a1cb:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libesmtp
 * [new ref]         908ea1d86f1ad9fe3bb8affe8c42f657b5f3a1cb -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 908ea1d Eliminate use of obsolete %patchN syntax (#2283636)