Examine source code of chestnut tree

{
  "theme": {
    "images": {
      "theme_frame": "header.png"
    },
    "colors": {
      "frame": "#cfcfcf",
      "tab_background_text": "#1c0000"
    }
  },
  "version": "2.0",
  "name": "chestnut tree",
  "manifest_version": 2,
  "description": "close-up of a chestnut tree"
}