Examine source code of Webcron.org

{
  "theme": {
    "images": {
      "theme_frame": "webcron-personna1.png"
    },
    "colors": {
      "frame": "#bbbdc7",
      "tab_background_text": "#ffffff"
    }
  },
  "version": "2.0",
  "name": "Webcron.org",
  "manifest_version": 2,
  "description": "<a href=\"https://outgoing.prod.mozaws.net/v1/48817cad674b32f8c0a24e351c5a98cd38873aa6c91bf1b9be28a265b8934d26/http%3A//Webcron.org\" rel=\"nofollow\">Webcron.org</a> Persona"
}