Examine source code of Mission Playground

{
  "theme": {
    "images": {
      "theme_frame": "missionplaygroundheader2copy.jpg"
    },
    "colors": {
      "frame": "#707070",
      "tab_background_text": "#000000"
    }
  },
  "version": "2.0",
  "name": "Mission Playground",
  "manifest_version": 2,
  "description": "Mission Playground has the right idea towards this kind of thing."
}