[Exim] Understanding time in message ID

Hi there guys.

Can someone please explain to me, how to understand the concept behind
an email message id.
E.G.

1AxkPR-00048U-00-H
1AxkPR-00048U-00-D

As explained in ref manual the first 6 char's is the way UNIX systems
read time.
Is the a way to convert this into something readable.

Regards
Marcus