Examine source code of IM

{
  "name": "IM",
  "version": "1.3resigned1",
  "description": "",
  "icons": {
    "16": "16.png",
    "48": "48.png",
    "128": "128.png"
  },
  "permissions": [
    "notifications",
    "tabs",
    "activeTab",
    "https://www.amazon.com/*",
    "https://itemmonitor.ideoclick.net/*",
    "https://implugin20180122121307.azurewebsites.net/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "manifest_version": 2,
  "browser_action": {
    "default_icon": "icon.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://www.amazon.com/*"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "web_accessible_resources": [
    "48.png"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{748165e6-ac57-4e30-8942-3a6709f6a3c7}"
    }
  }
}