Examine source code of Slytom Header

{
  "theme": {
    "images": {
      "theme_frame": "ffheader.png"
    },
    "colors": {
      "frame": "rgba(229,230,232,1)",
      "tab_background_text": "#000"
    }
  },
  "version": "2.0",
  "name": "Slytom Header",
  "manifest_version": 2,
  "description": "<a href=\"https://outgoing.prod.mozaws.net/v1/537c39a8030305d690469afcefb9ef1fbd543da5c6c338222a59f7dcbe67735d/Http%3A//Slytom.fr\" rel=\"nofollow\">Http://Slytom.fr</a>"
}