Examine source code of YouTube Eiko Progress Bar

{
  "manifest_version": 2,
  "name": "YouTube Orange Progress Bar",
  "version": "1.2",
  "description": "Recolors the YouTube progress bar to orange with a custom scrubber image.",
  "browser_specific_settings": {
    "gecko": {
      "id": "eiko-progress-bar@repaa.hu",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "content_scripts": [
    {
      "matches": [
        "*://www.youtube.com/*"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_end"
    }
  ],
  "web_accessible_resources": [
    "eiko.png",
    "eiko.webp"
  ]
}