Examine source code of Volume Scroller for YouTube™

{
  "manifest_version": 2,
  "name": "Volume Scroller for YouTube™",
  "description": "Control YouTube volume with your mouse scroll wheel. Works on YouTube videos, Shorts, YouTube Music, and embedded players.",
  "version": "1.0.0",
  "icons": {
    "16": "/icon/16.png",
    "32": "/icon/32.png",
    "48": "/icon/48.png",
    "96": "/icon/96.png",
    "128": "/icon/128.png"
  },
  "permissions": [
    "storage",
    "activeTab",
    "https://*.youtube.com/*",
    "https://www.youtube-nocookie.com/*"
  ],
  "browser_specific_settings": {
    "gecko": {
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      },
      "id": "{8c8e41d4-64d5-492c-973b-3a88772bb536}"
    }
  },
  "web_accessible_resources": [
    "youtube-main-world.js",
    "content-scripts/youtube.css"
  ],
  "browser_action": {
    "default_title": "Volume Scroller for YouTube™",
    "default_popup": "popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "https://*.youtube.com/*",
        "https://www.youtube-nocookie.com/embed/*"
      ],
      "all_frames": true,
      "run_at": "document_idle",
      "js": [
        "content-scripts/youtube.js"
      ]
    }
  ]
}