Examine source code of YouSlow

{
  "manifest_version": 3,
  "name": "YouSlow",
  "version": "0.4.0",
  "content_scripts": [
    {
      "matches": [
        "*://*.youtube.com/*"
      ],
      "js": [
        "src/youslow-inject.js"
      ]
    }
  ],
  "web_accessible_resources": [
    {
      "matches": [
        "<all_urls>"
      ],
      "resources": [
        "src/options.js"
      ]
    }
  ],
  "description": "Granular video speed control on YouTube",
  "browser_specific_settings": {
    "gecko": {
      "id": "youslow@ivanik.ru"
    }
  },
  "icons": {
    "48": "icons/icon48.png",
    "96": "icons/icon96.png",
    "256": "icons/icon256.png"
  },
  "action": {
    "default_title": "YouSlow",
    "default_popup": "src/pages/popup.html"
  },
  "options_ui": {
    "page": "src/pages/options.html"
  },
  "permissions": [
    "storage"
  ]
}