Examine source code of BNG - Compostela

{
  "theme": {
    "images": {
      "theme_frame": "firefoxbng_top.png"
    },
    "colors": {
      "frame": "#1b3863",
      "tab_background_text": "#1b3863"
    }
  },
  "version": "2.0",
  "name": "BNG - Compostela",
  "manifest_version": 2,
  "description": "<a href=\"https://outgoing.prod.mozaws.net/v1/e74eb49baa0e39cd2ce1bc545de8fabb2b7f3303642165fea5089273516d94d0/http%3A//www.bng-compostela.org\" rel=\"nofollow\">www.bng-compostela.org</a>"
}