Questions about track naming template

Been fiddling around with the Audio Tag File Naming Template and have a few questions:

What role does putting the brackets around %N. play? Doesn’t seem to make any difference?

Except, when I try to bold the artist like this:

[%N.] [%A]

It doesn’t display the artist in bold correctly, until I take away the %N brackets like this:

%N. [%A]

Also, in Estuary, it displays the Year first in a different colour. Like this

2017 1. Artist – Title

Where does the Year get specified, and how do I change the colour?

Thanks!