When a client is mapping a document containing text boxes, there is a banner at the top of the screen advising "Textboxes from a Word/PDF file will be removed, content within will be marked as "T" and excluded when exporting to source. Export via a Template for complete content transfer."
During a client training session, clicking the T box next to the Save button in the upper right should allow the client to scroll through and see the boxes, similar to viewing unmarked content. All content was grayed out and scrolling did not show anything marked as a text box.
This was replicated and confirmed by product.