Examine source code of Espresso

{
  "theme": {
    "images": {
      "theme_frame": "espresso_header.jpg"
    },
    "colors": {
      "frame": "#d3caaa",
      "tab_background_text": "#363330"
    }
  },
  "version": "2.0",
  "name": "Espresso",
  "manifest_version": 2,
  "description": "Based on Espresso 0.1 found on <a href=\"https://outgoing.prod.mozaws.net/v1/e9f34e4b339ba3d84699dbd26530877d5aa2f3d89ad74f8f990faffcb73f89ea/http%3A//xfce-look.org\" rel=\"nofollow\">xfce-look.org</a>"
}