Examine source code of Illustrius

{
  "theme": {
    "images": {
      "theme_frame": "TopBannerAiFF.png"
    },
    "colors": {
      "frame": "#8c6565",
      "tab_background_text": "#1c1313"
    }
  },
  "version": "2.0",
  "name": "Illustrius",
  "manifest_version": 2,
  "description": "Done with Illustrator as an exercise"
}