Examine source code of UsandoMac

{
  "theme": {
    "images": {
      "theme_frame": "UsandoMacHeader6.png"
    },
    "colors": {
      "frame": "#b8b6b6",
      "tab_background_text": "#030303"
    }
  },
  "version": "2.0",
  "name": "UsandoMac",
  "manifest_version": 2,
  "description": "Clean metal look.\nLimpia vista metalica.\n<a href=\"https://outgoing.prod.mozaws.net/v1/dd3051e1739e8dce17cd2cf7e12028194c0a5bc0e93eb18d5a7d00195030f571/http%3A//usandomac.blogspot.com/\" rel=\"nofollow\">http://usandomac.blogspot.com/</a>"
}