Examine source code of YouTube Equalizer

{
  "manifest_version": 3,
  "name": "YouTube Equalizer",
  "version": "1.0",
  "description": "A YouTube Equalizer for HTML5 video and audio with presets.",
  "permissions": [
    "activeTab",
    "scripting",
    "storage"
  ],
  "host_permissions": [
    "https://www.youtube.com/*",
    "https://m.youtube.com/*"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "youtube-eq@example.com",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "action": {
    "default_popup": "popup.html",
    "default_title": "Audio EQ"
  },
  "content_scripts": [
    {
      "matches": [
        "https://www.youtube.com/*",
        "https://m.youtube.com/*"
      ],
      "js": [
        "content.js"
      ],
      "all_frames": true
    }
  ]
}