[exim] interpreting exim -bt

hi all,

# exim -bt post@???
post@??? -> /path/to/Maildir/
   transport = address_directory
post@???
     <-- post@???
     <-- post@???
   router = remoteusers, transport = remote_smtp
   host mx00.kundenserver.de [212.227.15.150] MX=10
   host mx00.kundenserver.de [212.227.15.134] MX=10
   host mx00.kundenserver.de [212.227.15.186] MX=10
   host mx00.kundenserver.de [212.227.15.169] MX=10

It's clear, that we have a local delivery and an external one.

But what do those two "<--" mean exactly ?

best regards,
Marius