Examine source code of Pace Reader

{
  "manifest_version": 3,
  "name": "Pace Reader",
  "version": "1.1",
  "description": "A Firefox extension for pace reading.",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "css": [
        "src/styles/overlay.css"
      ],
      "js": [
        "src/textExtractor.js",
        "src/wordPlayback.js",
        "src/progressBar.js",
        "src/uiControls.js",
        "src/themes.js",
        "src/overlay.js",
        "src/eventHandlers.js",
        "src/main.js"
      ]
    }
  ],
  "permissions": [
    "activeTab",
    "scripting"
  ],
  "web_accessible_resources": [
    {
      "resources": [
        "images/play-button.png",
        "images/pause-button.png",
        "images/rewind-icon.png",
        "images/typography-icon.png",
        "images/close-icon.png",
        "images/light-icon.png",
        "images/dark-icon.png",
        "images/sepia-icon.png"
      ],
      "matches": [
        "<all_urls>"
      ]
    }
  ],
  "action": {
    "default_icon": {
      "16": "images/icon-16.png",
      "48": "images/icon-32.png",
      "128": "images/icon-128.png"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "pacereaderapp@gmail.com",
      "strict_min_version": "91.0"
    }
  }
}