Debugging is when you open up the back of your tamagotchi, unskrew the four little skrews, and with a pencil, rub the cemicircles.
Debugging allows you to choose the character you want, plus make your tamagotchi go at hyperspeed.
I think it is what bandai uses to test out animations and events on the tamagotchi.
Please note that you can only debugg a connection, plus, or keitai.
If you debugg a v3, you will not be able to enter a username, threrefore you cannot use tamatown or enter passwords.