Internet Engineering Task Force(IETF)は、適切なRFCであるRFC 6154でそれを定義しています。そこには、特別な用途のメールボックス宗派のリストがあります。
\All
This mailbox presents all messages in the user's message store.
Implementations MAY omit some messages, such as, perhaps, those
in \Trash and \Junk. When this special use is supported, it is
almost certain to represent a virtual mailbox.
\Archive
This mailbox is used to archive messages. The meaning of an
"archival" mailbox is server-dependent; typically, it will be
used to get messages out of the inbox, or otherwise keep them
out of the user's way, while still making them accessible.
\Drafts
This mailbox is used to hold draft messages -- typically,
messages that are being composed but have not yet been sent. In
some server implementations, this might be a virtual mailbox,
containing messages from other mailboxes that are marked with
the "\Draft" message flag. Alternatively, this might just be
advice that a client put drafts here.
\Flagged
This mailbox presents all messages marked in some way as
"important". When this special use is supported, it is likely
to represent a virtual mailbox collecting messages (from other
mailboxes) that are marked with the "\Flagged" message flag.
\Junk
This mailbox is where messages deemed to be junk mail are held.
Some server implementations might put messages here
automatically. Alternatively, this might just be advice to a
client-side spam filter.
\Sent
This mailbox is used to hold copies of messages that have been
sent. Some server implementations might put messages here
automatically. Alternatively, this might just be advice that a
client save sent messages here.
\Trash
This mailbox is used to hold messages that have been deleted or
marked for deletion. In some server implementations, this might
be a virtual mailbox, containing messages from other mailboxes
that are marked with the "\Deleted" message flag.
Alternatively, this might just be advice that a client that
chooses not to use the IMAP "\Deleted" model should use this as
its trash location. In server implementations that strictly
expect the IMAP "\Deleted" model, this special use is likely not
to be supported.
Norman Schmidt
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