Examine source code of Letterland

{
  "theme": {
    "images": {
      "theme_frame": "Firefox-Persona-abc.jpg"
    },
    "colors": {
      "frame": "rgba(229,230,232,1)",
      "tab_background_text": "#000"
    }
  },
  "version": "2.0",
  "name": "Letterland",
  "manifest_version": 2,
  "description": "Letterland is a leading child friendly phonics publisher making learning multi-sensory for over 40 years. For more information see <a href=\"https://outgoing.prod.mozaws.net/v1/6cf88ffbe6bffa58ef61423a3908eee5b214e09308996d3fc32967e2c6ebdc96/http%3A//www.letterland.com\" rel=\"nofollow\">www.letterland.com</a>"
}