Examine source code of Metal sonic

{
  "theme": {
    "images": {
      "theme_frame": "MetalSonicFIreFoxbanner.png"
    },
    "colors": {
      "frame": "#9e0000",
      "tab_background_text": "#000545"
    }
  },
  "version": "2.0",
  "name": "Metal sonic",
  "manifest_version": 2,
  "description": "Just a thing i doodled and decided to turn it into my own Firefox banner so everyone could use it :3"
}