AT&T Galaxy S8 What is stealth mode in the secret codes list?

[anon(10181084)]

So recently I got a Galaxy S8 on Straight Talk. I've been playing around with some stuff and noticed in the list of secret codes something called STEALTHMODE (see screenshot below). What could this be? Is this some sort of anti-triangulation feature I could use or something I am totally unaware of? I haven't noticed it on any of my previous Android devices.

 

[mustang7757]

These are secret dialer codes some might work and others not .