[Mailman-Developers] Why both a .msg and .db in qfiles?

[JasonR.Mastaler]

For every incoming message waiting to be posted, MM writes both a .msg
file containing the message text, and a .db file containing
meta-information about that message.

I'm curious why MM doesn't just store the rfc822 headers and message
body in the .db pickle/marshal as well?  Why maintain two files
instead of just one?

The reason I ask is because I'm contemplating a similar approach for
TMDA.

Thanks.

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