Contains a broken down database representation of the From, To, Cc ReplyTo, and Bcc addresses for each message.
Structure of mail_addresses
Unique internal identifier of the message.
Unique internal identified of a recipient.
A constant integer that identifies the header where the email address is referenced. The possible values are:
Bcc (only for outgoing messages): 5
The position of the address (starting from 0) in the header when it contains a list of addresses.