Examine source code of Gradient Generator

{
  "manifest_version": 2,
  "name": "Gradient Generator",
  "version": "1.1",
  "description": "Generate CSS gradients easily.",
  "permissions": [
    "activeTab"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "icon128.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "icons": {
    "48": "icon48.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{34b4a946-c7a8-40ad-94c0-86566268397b}"
    }
  }
}