Examine source code of Chronio URL Saver

{
  "manifest_version": 2,
  "name": "Chronio URL Saver",
  "version": "1.5.0",
  "description": "Quickly save any page to your Chronio Library",
  "browser_specific_settings": {
    "gecko": {
      "id": "chronio-url-saver-2@chronioapp.com",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "permissions": [
    "<all_urls>",
    "tabs",
    "activeTab",
    "storage",
    "alarms",
    "https://chronioapp.com/*",
    "https://api.chronioapp.com/*",
    "http://localhost:3000/*",
    "http://localhost:5000/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://chronioapp.com/*",
        "http://localhost:3000/*"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icons/icon-16.png",
      "48": "icons/icon-48.png",
      "128": "icons/icon-128.png"
    }
  }
}