Examine source code of PushEngage: Web & App Push Notifications

{
  "manifest_version": 2,
  "name": "PushEngage: Web & App Push Notifications",
  "description": "Create and send web push notifications from any page, plus app push to Android and iOS. AI copy, segments, click stats.",
  "version": "1.0.0",
  "short_name": "PushEngage",
  "icons": {
    "16": "icon/16.png",
    "32": "icon/32.png",
    "48": "icon/48.png",
    "128": "icon/128.png",
    "256": "icon/256.png",
    "512": "icon/512.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "extension@pushengage.com",
      "data_collection_permissions": {
        "required": [
          "authenticationInfo",
          "websiteContent"
        ],
        "optional": [
          "technicalAndInteraction"
        ]
      }
    }
  },
  "permissions": [
    "activeTab",
    "tabs",
    "scripting",
    "storage",
    "alarms",
    "https://api-ext.pushengage.com/*",
    "https://app.pushengage.com/*"
  ],
  "optional_permissions": [
    "notifications",
    "<all_urls>"
  ],
  "commands": {
    "create-campaign": {
      "suggested_key": {
        "default": "Alt+Shift+P",
        "mac": "Command+Shift+P"
      },
      "description": "Create a push campaign from the current page"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_title": "PushEngage",
    "default_popup": "popup.html"
  }
}