$ git clone -n https://src.fedoraproject.org/rpms/mimedefang.git /var/lib/mock/f42-build-side-1-3517647-46098/root/chroot_tmpdir/scmroot/mimedefang
Cloning into '/var/lib/mock/f42-build-side-1-3517647-46098/root/chroot_tmpdir/scmroot/mimedefang'...
$ git fetch origin 065775a47287d500555a58409e7ad6586eb2b16d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mimedefang
 * [new ref]         065775a47287d500555a58409e7ad6586eb2b16d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 065775a Upgrade to 3.6 (#2301647)