Examine source code of Pointofmail.com Email Tracking & Recall

{
  "browser_specific_settings": {
    "gecko": {
      "id": "extension@pointofmail.com",
      "strict_min_version": "42.0"
    }
  },
  "background": {
    "service_worker": "js/service_worker.js",
    "scripts": [
      "js/pointofmail.js",
      "js/background.js"
    ]
  },
  "action": {
    "default_icon": "img/pom.png",
    "default_title": "Send via Pointofmail.com "
  },
  "content_scripts": [
    {
      "js": [
        "js/content.js"
      ],
      "matches": [
        "https://mail.google.com/*"
      ],
      "run_at": "document_idle"
    }
  ],
  "description": "Know who opens your emails, links and attachments, where and for how long. Recall and send self-destructed emails.",
  "icons": {
    "16": "img/pom-16.png",
    "48": "img/pom-48.png",
    "128": "img/pom-128.png"
  },
  "manifest_version": 3,
  "name": "Pointofmail.com Email Tracking & Recall",
  "host_permissions": [
    "https://*/*",
    "http://*/*"
  ],
  "short_name": "Pointofmail",
  "version": "6.1.2",
  "web_accessible_resources": [
    {
      "resources": [
        "js/service_worker.js",
        "js/jquery-4.0.0-beta.js",
        "js/tooltip.min.js",
        "js/purify.min.js",
        "js/gmail.js",
        "js/scheduler.js",
        "js/pointofmail.js",
        "js/toolbar.js",
        "js/main.js",
        "css/pom.css",
        "css/tooltip.css",
        "start.html"
      ],
      "matches": [
        "https://mail.google.com/*"
      ]
    }
  ]
}