Examine source code of Free Rider Mod Manager

{
  "name": "Free Rider Mod Manager",
  "version": "0.0.1",
  "author": "Calculamatrise",
  "description": "A mod manager for Free Rider HD.",
  "manifest_version": 3,
  "action": {
    "default_popup": "popup/index.html"
  },
  "background": {
    "scripts": [
      "service-worker.js"
    ],
    "type": "module"
  },
  "icons": {
    "16": "icons/icon_16.png",
    "48": "icons/icon_48.png",
    "128": "icons/icon_128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "frhd-script-manager@freeriderhd.com"
    }
  },
  "permissions": [
    "scripting",
    "storage",
    "webNavigation"
  ],
  "host_permissions": [
    "*://frhd.kanoapps.com/*",
    "*://www.freeriderhd.com/*"
  ],
  "options_ui": {
    "page": "dashboard/index.html",
    "open_in_tab": true
  },
  "web_accessible_resources": [
    {
      "resources": [
        "game/*",
        "shared/*"
      ],
      "matches": [
        "*://frhd.kanoapps.com/*",
        "*://www.freeriderhd.com/*"
      ]
    }
  ]
}