Examine source code of Speed Reader

{
  "manifest_version": 3,
  "name": "Speed Reader",
  "version": "1.6",
  "description": "Speed-read the web",
  "homepage_url": "https://github.com/filipesabella/speed-reader",
  "browser_specific_settings": {
    "gecko": {
      "id": "{9ad66b79-fd5e-477a-8915-eea26c83ff42}",
      "strict_min_version": "109.0"
    }
  },
  "icons": {
    "48": "icons/speed-reader-48.png",
    "96": "icons/speed-reader-96.png"
  },
  "permissions": [
    "contextMenus",
    "activeTab",
    "storage",
    "scripting"
  ],
  "action": {
    "default_icon": "icons/speed-reader-36.png",
    "default_title": "Speed Reader"
  },
  "commands": {
    "_execute_action": {
      "suggested_key": {
        "default": "Ctrl+Alt+U"
      },
      "description": "Speed-read the selected text"
    }
  },
  "background": {
    "scripts": [
      "build/extension.js"
    ],
    "service_worker": "build/extension.js"
  },
  "options_ui": {
    "page": "build/settings.html"
  }
}