Config Mode?

Config Mode?

I have seen several references to a Config mode, someone said the mouse wouldn't switch profiles when in Config mode. But I cant find anything explaining what config mode is or what it is for.
I think I understand that it is activated when tilt hits 25 degrees and that some of the global settings affect  being able to use Config mode. but that's the extent of what I could find.

Side note, I also haven't been able to find enough on the Joystick setting/function to understand what that is for or why it exists (probably because I'm not a gamer, but still curious about its use)

thanks for any knowledge