Examine source code of fannechat

{
  "manifest_version": 2,
  "name": "fannechat",
  "version": "0.1.1",
  "description": "Connect fans of different languages through chat.",
  "icons": {
    "48": "icons/icon48.png",
    "96": "icons/icon96.png"
  },
  "options_ui": {
    "page": "options.html"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.youtube.com/*"
      ],
      "js": [
        "youtube.js"
      ]
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "page_action": {
    "browser_style": true,
    "default_icon": {
      "19": "icons/icon19.png",
      "38": "icons/icon38.png"
    },
    "default_title": "Translate",
    "default_popup": "popup.html"
  },
  "applications": {
    "gecko": {
      "id": "fannechat@chikage.net"
    }
  },
  "permissions": [
    "*://*/*",
    "storage"
  ]
}