Examine source code of QuickNav for Salesforce

{
  "manifest_version": 2,
  "name": "QuickNav for Salesforce",
  "version": "1.1.1resigned1",
  "icons": {
    "16": "icons/16.png",
    "48": "icons/48.png",
    "128": "icons/128.png"
  },
  "author": "Jeff Hube",
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.salesforce.com/*",
        "*://*.force.com/*",
        "*://*.cloudforce.com/*"
      ],
      "css": [
        "content.css"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "permissions": [
    "*://*.salesforce.com/*",
    "*://*.force.com/*",
    "*://*.cloudforce.com/*",
    "storage",
    "tabs"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{ac18a1f5-9424-434a-a6e2-af46416ab4fd}"
    }
  }
}