Examine source code of Dragon Sketch

{
  "theme": {
    "images": {
      "theme_frame": "DragonSketch.jpg"
    },
    "colors": {
      "frame": "#2b2b2b",
      "tab_background_text": "#000000"
    }
  },
  "version": "2.0",
  "name": "Dragon Sketch",
  "manifest_version": 2,
  "description": "Dragon sketch based on Lockwood's Hummingbird Feeder. Drawn for tattoo. Overlaid on banana paper in photoshop for nice texture."
}