Examine source code of Filemail

{
  "theme": {
    "images": {
      "theme_frame": "Persona_Filemail.png"
    },
    "colors": {
      "frame": "#c9c9c9",
      "tab_background_text": "#000000"
    }
  },
  "version": "2.0",
  "name": "Filemail",
  "manifest_version": 2,
  "description": "Tribute to <a href=\"https://outgoing.prod.mozaws.net/v1/941aa34b086ce6c4933ca6c6912af20dd3d8fd4ba947918f76ed160b07732c06/http%3A//Filemail.com\" rel=\"nofollow\">Filemail.com</a>"
}