Examine source code of YouTube Quick Unsubscribe

{
  "manifest_version": 3,
  "name": "Subscription Feed Quick Toggle",
  "version": "1.0.0",
  "description": "Adds quick unsubscribe and re-subscribe buttons to channel cards in the YouTube subscriptions feed.",
  "browser_specific_settings": {
    "gecko": {
      "id": "subscription-feed-quick-toggle@gridsixty-llc",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    },
    "gecko_android": {
      "strict_min_version": "142.0"
    }
  },
  "action": {
    "default_icon": {
      "16": "icons/icon16.svg",
      "48": "icons/icon48.svg",
      "128": "icons/icon128.svg"
    },
    "default_title": "Subscription Feed Quick Toggle"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.youtube.com/feed/subscriptions*"
      ],
      "js": [
        "content.js"
      ],
      "css": [
        "content.css"
      ],
      "run_at": "document_idle"
    }
  ],
  "icons": {
    "16": "icons/icon16.svg",
    "48": "icons/icon48.svg",
    "128": "icons/icon128.svg"
  }
}