Examine source code of Olive Tree

{
  "theme": {
    "images": {
      "theme_frame": "7b.jpg"
    },
    "colors": {
      "frame": "rgba(229,230,232,1)",
      "tab_background_text": "#000"
    }
  },
  "version": "2.0",
  "name": "Olive Tree",
  "manifest_version": 2,
  "description": "Very simple FF persona based on some of our corporate colours - built for internal use - but you may like it!"
}