6.1's New Colour System

[Lyim]

I am a little confused, what are these numbers supposed to mean?
I thought it was RGB but with the 4th number being brightness or contrast but that doesn't seem to be the case.

I insert a Red RGB value and get Blue, a Green RGB value and get Black, a Yellow RGB value and get Pink. 

Would anyone be able to tell me what this is and if so could you link me to a colour picker for it?

 

Code Snippet:

      "Aggressive": {
        "Name": "255,0,0,255",
        "Outline": "255,0,0,0",
        "Background": "180,0,0,0"
      }

 

[jcsnider]

ARGB

 

First number is alpha. 255 is visible and 0 is invisble

[Lyim]

Ahh, thank-you!