Changes in Thunderbird 106
default_windowsmanifest property, to allow a browserAction buttons to be displayed in stand alone message windows.
tabparameter to onCommand, to get information about the active tab, when a command occurs.
Added getPhoto(id) to be able to retrieve the photo of a contact.
messagemember to the MessageAttachment type, to provide access to attached messages.
externalmember to the MessageHeader type, to indicate if a message is an external message, not stored in a message folder (message attachments or messages opened from file).
newmember to the MessageHeader type, to indicate if a message has been received recently and is marked as new.
Added import(file, destination, [properties]) to import messages into Thunderbird (currently only supported for local folders).
Fixed onMessageDisplayed to be triggered for external messages.