Examine source code of Calendar for YouTube

{
  "manifest_version": 3,
  "name": "Calendar for YouTube",
  "version": "1.1.1",
  "description": "Adds a simple Calendar chip to a YouTube channel's Videos tab.",
  "browser_specific_settings": {
    "gecko": {
      "id": "calendar-for-youtube@slyva.dima",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    },
    "gecko_android": {
      "strict_min_version": "142.0"
    }
  },
  "permissions": [
    "storage"
  ],
  "options_ui": {
    "page": "src/options.html",
    "open_in_tab": true
  },
  "icons": {
    "16": "icons/icon16.png",
    "32": "icons/icon32.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://www.youtube.com/*"
      ],
      "js": [
        "src/content.js"
      ],
      "css": [
        "src/calendar.css"
      ],
      "run_at": "document_idle"
    }
  ]
}