Examine source code of VIFPO

{
  "manifest_version": 2,
  "name": "VIFPO",
  "version": "0.2resigned1",
  "description": "Vim navigation and other vim like actions in Firefox. See Documentation for more information.",
  "icons": {
    "48": "icons/page-32.png"
  },
  "content_scripts": [
    {
      "matches": [
        "http://*/*",
        "https://*/*"
      ],
      "js": [
        "build/content.js"
      ]
    }
  ],
  "background": {
    "scripts": [
      "build/background.js"
    ]
  },
  "browser_action": {
    "browser_style": true,
    "default_popup": "build/input.html",
    "default_icon": {
      "16": "icons/page-16.png",
      "32": "icons/page-32.png"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{8479a06c-24d0-44f4-abbe-4a0909eebbea}"
    }
  }
}