Two silly questions

Hey dudes!
So, not wasting a time on a broad intorduction, I here present my questions

1: What's the difference between 'library' and 'library_once'?
2: What's the point of the 'debug' prefix before a call?

Help's appreciated!

Quotes from JassHelper manual.

also no time for manual ,readme, forum FAQ and other threads...

The reason I rather asked in person what they did is that I don't understand the vJass Manual. It's a little too advanced language for me and reading it often results in even more questions.
That 'debug' quote made sence, though I still don't know what library_once does... Can I declare a library with the same name twice, just that one of them won't compile?

if you have problems with english use any translator (promt ex)

library_once:
normally, if you declare two libraries that have the same name, you will get a syntax error. however, if you declare a library with library_once instead, the second library will simply be ignored(thats what I understood from "it would just ignore the second declaration and avoid to add its contents instead of showing a syntax error")

Makes sence, but how is that useful? Why not just replace the former library, or rename it?
There was something about textmacros, but I havn't found their purpose useful enough to start learning them, yet.
What you said was basically what I thought, just that I wanted some kind of confirmation, cause - in my mind - they don't make much sence.

Any concrete example of its use? I noticed it in the TimerUtils library, but it might aswell use library instead.

I'm not sure why TimerUtils uses it, either.