Examine source code of Local

{
  "manifest_version": 2,
  "name": "Local",
  "description": "Find Amazon products locally. Get what you want today, with no shipping cost!",
  "version": "4.0",
  "permissions": [
    "activeTab",
    "declarativeContent"
  ],
  "host_permissions": [
    "*://*/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://www.amazon.ca/*",
        "https://www.amazon.co.uk/*",
        "https://www.amazon.at/*",
        "https://www.amazon.de/*"
      ],
      "js": [
        "contentScript.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "local@extension.com",
      "strict_min_version": "42.0"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_action": {
    "default_icon": {
      "16": "images/icons8-shop-local-16.png",
      "32": "images/icons8-shop-local-32.png",
      "48": "images/icons8-shop-local-48.png",
      "100": "images/icons8-shop-local-100.png"
    },
    "default_popup": "popup.html"
  },
  "icons": {
    "16": "images/icons8-shop-local-16.png",
    "32": "images/icons8-shop-local-32.png",
    "48": "images/icons8-shop-local-48.png",
    "100": "images/icons8-shop-local-100.png"
  }
}