GB News Debug Screen?
 

Just noticed in my area that GB News is carrying teletext data (my Samsung TV puts a D logo on the EPG).
My TV is not internet connected so I don't know if this is a debug screen associated with an Freeview internet app.

If I press TTX button 10 times (not red button) on GB News a blue debug screen will appear.

Is this GB News testing TTX services/app or is it something from the local transmitter?