Examine source code of Butterfly Fields

{
  "theme": {
    "images": {
      "theme_frame": "butterflybar_horiz.jpg"
    },
    "colors": {
      "frame": "#4d0dba",
      "tab_background_text": "#2dd4a2"
    }
  },
  "version": "2.0",
  "name": "Butterfly Fields",
  "manifest_version": 2,
  "description": "Butterflies in fields."
}