fe222425_lla_X_Mozilla_Status_explained_X_Mozilla_Status_Description
[Name] MSG_FLAG_QUEUED [Value] 0x0800 [Description] 
If set, this message is queued for delivery. This only ever gets set on messages in the queue folder, but is used to protect against the case of other messages having made their way in there somehow – if some other program put a message in the queue, it won't be delivered later!
Christian Eyrich - Mozilla X-Mozilla-Status explained
Description