Examine source code of Field Mustard View

{
  "theme": {
    "images": {
      "theme_frame": "header.png"
    },
    "colors": {
      "frame": "#ffffff",
      "tab_background_text": "#000000"
    }
  },
  "version": "2.0",
  "name": "Field Mustard View",
  "manifest_version": 2,
  "description": "Yellowish theme with a side image of a peaceful countryside of field-mustard flowers obtained from <a rel=\"nofollow\" href=\"https://outgoing.prod.mozaws.net/v1/a4dda70f4f37e00acd5cf4f78f966129562ed228ae0e96231ac8b1cfdf4f434d/http%3A//miriadna.com\">miriadna.com</a>"
}