Examine source code of Greybird

{
  "theme": {
    "images": {
      "theme_frame": "header.png"
    },
    "colors": {
      "frame": "#cecece",
      "tab_background_text": "#000000"
    }
  },
  "version": "2.0",
  "name": "Greybird",
  "manifest_version": 2,
  "description": "This theme is designed to complement the Gnome theme Greybird here: <a rel=\"nofollow\" href=\"https://outgoing.prod.mozaws.net/v1/60948fcf13c773394d4f9ce2a43a8ee68625b224112d9feb12938d926eecb57b/http%3A//satya164.deviantart.com/art/Greybird-GTK3-Theme-322365199\">http://satya164.deviantart.com/art/Greybird-GTK3-Theme-322365199</a>"
}