Another test on Gmail email manipulation. When exporting an email via Google Takeout, the product applies 3 headers specific to the email, including X-GM-THRID and X-Gmail-Labels and a line separator. What I noticed is that importing the original email without edits, the Mbox file headers do not appear, however if the original email is edited, the Mbox file headers appear. Is there a reason why it shows when the original email is edited but not if it is in its original form? Why can't the 3 headers be deleted when editing and subsequently trying to import back to Gmail via Thunderbird?