Examine source code of Goodbye Metrics

{
  "description": "Goodbye Metrics allows you to hide key metrics on YouTube.  You can block everything or just the ones that nag at you the most.",
  "version": "0.0.4",
  "manifest_version": 2,
  "name": "Goodbye Metrics",
  "browser_action": {
    "default_title": "Goodbye Metrics",
    "default_popup": "popup.html"
  },
  "background": {
    "persistent": false,
    "scripts": [
      "background.bundle.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "https://*.youtube.com/*"
      ],
      "js": [
        "contentScript.bundle.js"
      ],
      "css": [
        "content.styles.css"
      ],
      "run_at": "document_start"
    }
  ],
  "icons": {
    "128": "icon-128.png"
  },
  "permissions": [
    "activeTab",
    "storage"
  ],
  "content_security_policy": "script-src 'self' https://*.google-analytics.com; object-src 'self'",
  "browser_specific_settings": {
    "gecko": {
      "id": "support@slowgrowth.com"
    },
    "edge": {
      "browser_action_next_to_addressbar": true
    }
  }
}