Examine source code of lightspeed.ff

{
  "manifest_version": 3,
  "name": "lightspeed.ff",
  "version": "3.0.0",
  "description": "Keyboard access to every interactable element on a page",
  "icons": {
    "48": "icons/falling-star-48.png",
    "128": "icons/falling-star-128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{7133995c-ca91-4349-979f-602eb72987e3}",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    },
    "gecko_android": {
      "strict_min_version": "142.0"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content/index.js"
      ],
      "run_at": "document_start"
    }
  ]
}