Modelling Formatting - Yellow Fill In-Model

I've been self-teaching modelling, and I had a quick question for the experienced folk here.

I've seen a number of models with cells outlined and filled with yellow that aren't clearly listed under assumptions (e.g. in a revenue schedule for a retail company the comparable store sales growth being formatted this way for projected years). I've also noticed that the font in these cells tends to be blue, regardless of if it is actually hardcoded or not.

Could anyone lend some insight into the purpose of this formatting and when I would want to use it, and also why the blue font for non-hardcodes?