
An IMAP URL naming a message, or a part of it, for CATENATE (RFC 5092)
Source:R/raw-extensions-int.R
imap_url.RdBuilds the relative URL that ImapCon$append_catenate() uses to refer
to a message stored on the server: /<folder>;UID=<uid> with an
optional /;SECTION=<section> (e.g. "HEADER", "TEXT",
or a MIME part number such as "2").