On Thu, Jan 29, 2026 at 12:21:18PM -0500, Derek Martin wrote:
[RFC 4155]
It's an information-only RFC, it's not standards track. It was a
sly attempt to sneak in a standard for mbox, when there already
existed numerous contradictory implementations for decades before it
was published. In short, it's bunk, and should never have been
published. Your XKCD reference is on point.
Agreed.
Furthermore, it has a bug. It finds message boundaries by looking for a
From_ line with an exact syntax, but does not escape such lines in
messages. If somebody includes a sample mbox From_ line with that
syntax in the body of a message -- say in a discussion about
implementing mbox -- RFC 4155 will mistakenly take that as the
beginning of a new message.
I advise everybody to ignore RFC 4155.
