What is “NNTOOR” ???

It’s an acronym meaning “No Need To Open Or Respond” as a courtesy for the email recipient..

In other words:

1. The email’s subject line contains all of the info the email message seeks to convey

2. There’s no need for you to open it

3. There’s no need for you to respond to the email, though you are of course welcome to if that is your preference.

4. The NNTOOR sender is demonstrating respect for the recipient’s time and seeks to make email communication more efficient.