Examine source code of River Birch

{
  "theme": {
    "images": {
      "theme_frame": "header.png"
    },
    "colors": {
      "frame": "#f0e5e2",
      "tab_background_text": "#360505"
    }
  },
  "version": "2.0",
  "name": "River Birch",
  "manifest_version": 2,
  "description": "The trunk of a river birch tree in sunlight"
}