Robert works on the email side of the catalogue, building against RFC 5322 and the MIME specifications rather than against a handful of test files. Header decoding, attachment handling and the malformed messages that only ever turn up in real mailboxes are his.
6 articles by Robert Smith.
Two questions sort all of them. One message or a whole mailbox. Published structure or private. Everything else about portability follows from those two answers.
Every value sits in its own stream named __substg1.0_0037001F or similar. Nothing in the file says which of those is the subject line.
The format has no version and no variants. Everything awkward about EML comes from the folder around it rather than from anything inside the file.
The file copies perfectly. Outlook on the other machine is what refuses it, over one record written inside the file.
Rules, views, categories and search folders all live in there beside the mail. None of them survive a move to any other format.
Plain text, no index and no specification for its first thirty years. That history explains the four variants, the size on disk and why Outlook will not touch it.