Examine source code of influenza-gradient

{
  "theme": {
    "images": {
      "theme_frame": "header.png"
    },
    "colors": {
      "frame": "#3e4466",
      "tab_background_text": "#ffffff"
    }
  },
  "version": "2.0",
  "name": "influenza-gradient",
  "manifest_version": 2,
  "description": "Gradient from <a rel=\"nofollow\" href=\"https://outgoing.prod.mozaws.net/v1/bc032cc49f2b4fdeb8d4eff562ebc69738543a2bbf67109b467a097957d68d80/http%3A//uiGradients.com\">uiGradients.com</a>"
}