Examine source code of gifinder.org

{
  "theme": {
    "images": {
      "theme_frame": "header.png"
    },
    "colors": {
      "frame": "rgba(229,230,232,1)",
      "tab_background_text": "#000"
    }
  },
  "version": "2.0",
  "name": "gifinder.org",
  "manifest_version": 2,
  "description": "Search for the perfect GIFs with easy instant-search.\n\nOvers 4,000,000+ GIFs available to instant-search for that perfect description, animated gifs, person, or thing.\nAddon uses 3rd party site (<a rel=\"nofollow\" href=\"https://outgoing.prod.mozaws.net/v1/e6bdeba7ba2e4f8e9fd75c9456f00f4af965570ced58b2eee84fc7b852d2c5e5/http%3A//www.gifinder.org\">www.gifinder.org</a>) for operation"
}