What is the meaning of '$'

[swork1]

What is the meaning of needing a '$' in each sd7 file? For example

$ include "seed7_05.s7i";
  include "rational.s7i";

As without the '$' it will not compile. The only explanation I could find was in theSyntax part of the manual stating

The $ is used to introduce all hard coded statements.

Is there a better explanation somewhere that I'm missing?

[ThomasMertes]

I just improved the (already existing) FAQ answer regarding:
Why are there dollar signs in some places?
If you have more questions don't hesitate to ask.

[swork1]

Thanks makes sense, must have missed that faq