Examine source code of Apple Gradient Silver

{
  "theme": {
    "images": {
      "theme_frame": "AppleGradientSilver.png"
    },
    "colors": {
      "frame": "#74a3fc",
      "tab_background_text": "#121217"
    }
  },
  "version": "2.0",
  "name": "Apple Gradient Silver",
  "manifest_version": 2
}