Thunderbird’s X-Mozilla-Status and X-Mozilla-Status2 flags

Vincent Bernat

Thunderbird stores mails in the mbox format. In addition to the header lines set by the MUA or by the MTAs in transit, Thunderbird stores the message status in two headers: X-Mozilla-Status and X-Mozilla-Status2. These headers are hexadecimal representations of the message flags.

The content of the following tables are extracted from the source code of Thunderbird 102.


Flag Name Description
0x00000001 Read This message has been read
0x00000002 Replied A reply to this message has been successfully sent
0x00000004 Marked This message has been flagged
0x00000008 Expunged This message has already gone, but the folder hasn’t been compacted yet
0x00000010 HasRe The subject of this message has “Re:” on the front
0x00000020 Elided The children of this sub-thread are folded in the display
0x00000040 FeedMsg The message is a feed, originally downloaded in a server.type=rss account
0x00000080 Offline This news article or IMAP message is present in the disk cache
0x00000100 Watched This thread is being watched
0x00000200 SenderAuthed This message’s sender has been authenticated when sending this message
0x00000400 Partial Partial message whose body should be downloaded from the POP server
0x00000800 Queue This message is queued for delivery
0x00001000 Forwarded This message has been forwarded
0x00002000 Redirected This message has been redirected
0x0000E000 Priorities These are used to remember the message priority


Flag Name Description
0x00010000 New This message is new since the last time the folder was closed
0x00040000 Ignored This thread has been ignored
0x00200000 IMAPDeleted This IMAP message has been marked deleted on the server
0x00400000 MDNReportNeeded This message has requested to send a message delivery notification to its sender
0x00800000 MDNReportSent A message delivery notification has been sent for this message
0x01000000 Template This message is a template
0x0E000000 Labels These are used to remember the message labels
0x10000000 Attachment This message has files attached to it