Use of 'DEBUG' does any known definitive reference exist ???

Learning/Reference gives guidance on all instructions without, from what I’ve been able to discover, a description on the correct way to use the DEBUG command with the Arduino IDE.

Here are 2 links re DEBUG but I’d welcome (beg) any other examples to share:

Regards all

DEBUG is not a command.

The Arduino environment does not have any debug commands available but you can create your own to a certain extent. The Wordpress page that you linked to shows one technique, namely defining DEBUG at the start of the program and selectively printing messages in the program if DEBUG is set to 1 (true) rather than 0 (false)

The debug statements created like this are compiled into the program when testing but once testing is complete and DEBUG is set to 0 and the program is compiled the associated debug statements are removed from the compiled code.

I don't there is any such thing as "the correct way". It is just a convenience to be used as you please.