Information regarding undocumented Unity features

In project code time to times used undocumented different Unity features, can anyone to describe that they do:

1. in EditorInitialisationLoader.cs

Code (CSharp):

1.     public int targetFramerate = 0; // For debugging purposes
2.     private void Awake()
3.     {
4.         Application.targetFrameRate = targetFramerate; // For debugging purposes

Which the reason to set this parameter into 0?
From Unity docs:

 

Hah I was just looking at this section of code a couple nights ago and thought the 0 was a little odd. After testing, it seems that 0 behaves the same as -1. So for practical purposes, I don't think this is that big of a deal. We could maybe add a tooltip explaining the behavior for different values?

Along these lines, would it be beneficial to be able to change the target frame rate during play mode instead of just on Awake? Found myself changing the value in the inspector expecting a frame rate change before remembering it is only set in Awake.

 

It's just a thing I left there as I was debugging something in case I needed to use it later, I don't think we need to build a feature out of it right now.