Examine source code of SolarizedDarkTheme

{
  "theme": {
    "images": {
      "theme_frame": "header.png"
    },
    "colors": {
      "frame": "#586e75",
      "tab_background_text": "#fdf6e3"
    }
  },
  "version": "2.0",
  "name": "SolarizedDarkTheme",
  "manifest_version": 2,
  "description": "Colors lifted from <a rel=\"nofollow\" href=\"https://outgoing.prod.mozaws.net/v1/84fc2a9889cf35b10644adef8f36c2af5f4beaf19955759761bceb2d20cfd051/http%3A//ethanschoonover.com/solarized\">http://ethanschoonover.com/solarized</a>."
}