Examine source code of FlashRead - RSVP Speed Reader

{
  "manifest_version": 3,
  "name": "FlashRead - RSVP Speed Reader",
  "version": "1.1.0",
  "description": "Speed read at 500-900+ WPM with RSVP. One word at a time, centered on the optimal recognition point.",
  "browser_specific_settings": {
    "gecko": {
      "id": "flashread@flashread.app",
      "strict_min_version": "126.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "icons": {
    "16": "icons/icon16.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "action": {
    "default_popup": "src/popup/popup.html",
    "default_icon": {
      "16": "icons/icon16.png",
      "48": "icons/icon48.png"
    },
    "default_title": "FlashRead - Speed Reader"
  },
  "background": {
    "scripts": [
      "src/background/service-worker.js"
    ],
    "type": "module"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "src/content/content.js"
      ],
      "css": []
    }
  ],
  "permissions": [
    "contextMenus",
    "activeTab",
    "storage",
    "scripting"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "options_page": "src/options/options.html",
  "commands": {
    "start-reading": {
      "suggested_key": {
        "default": "Ctrl+Shift+R",
        "mac": "MacCtrl+Shift+R"
      },
      "description": "Start speed reading selected text or article"
    }
  }
}