If exit IXZXIT01 appended additional data to the message in the form of a message extent, the message extent queue becomes the last section of the message packet. Note that each segment of a multi-segment message can have its own message extent queue. The message extent section includes:

• An 8-character name (used to identify the message extent to the exit)
• The message extent length
• A pointer to the message extent text
• A pointer to the next message extent.