Examine source code of Live Indicator

{
  "manifest_version": 2,
  "name": "Live Indicator",
  "version": "1.0",
  "description": "Adds a border to the web pages you specify.",
  "icons": {
    "48": "border-48.png"
  },
  "options_ui": {
    "page": "options.html",
    "browser_style": true
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "liveindicator.js"
      ]
    }
  ],
  "permissions": [
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "liveindicator@pluckypenguin.com"
    }
  }
}