Template After Effect construit de façon bizarre pour me

Hello to all,

I discovered, using an After Effect template, a way to work on After Effect that I don't understand (I attach

the image).

To summarize what I understand:
There is a null layer in which all the color properties are put: background color, text color, etc...

When I go to the corresponding background, I look for how it is linked to this property, but I can't find an expression or an element that makes the link.

Similarly on this template, you can see the "text holder" whose visibility has been disabled and yet appear on my motion design via a specific composition found in the imports but not integrated into this sequence. How do they do it?

Thanks in advance.