Fixes a bug where google streetview laggs horribly on 3rd party websites like Geotastic or geoguessr.

geogame-firefox-lag-fix.user.js

// ==UserScript==
// @name         Geotastic/guessr lag fix on Firefox Linux
// @namespace    http://tampermonkey.net/
// @version      0.2
// @description  Spoofs a Chromium-based user agent for geotastic.net and geoguessr.com to potentially improve performance.
// @author       Google Gemini 2.5 Pro
// @match        *://geotastic.net/*
// @match        *://www.geotastic.net/*
// @match        *://geoguessr.com/*
// @match        *://www.geoguessr.com/*
// @run-at       document-start
// @grant        none
// @updateURL    https://gist.github.com/Delivator/335f7a00a52b358e5398acdaf259bfb3/raw/geogame-firefox-lag-fix.user.js
// @downloadURL  https://gist.github.com/Delivator/335f7a00a52b358e5398acdaf259bfb3/raw/geogame-firefox-lag-fix.user.js
// ==/UserScript==

(function() {
    'use strict';

    // A common Chromium-based user agent string (e.g., from a recent version of Chrome on Windows)
    // You can update this to a more current one if needed by searching for "my user agent" in a Chrome browser.
    const chromeUserAgent = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/123.0.0.0 Safari/537.36";

    // Override the navigator.userAgent property
    Object.defineProperty(navigator, 'userAgent', {
        value: chromeUserAgent,
        writable: false,
        configurable: false
    });

    // Some sites might also check other navigator properties related to the user agent.
    // For a more thorough spoof, you might consider also spoofing these if issues persist:
    // Object.defineProperty(navigator, 'appVersion', { value: chromeUserAgent.replace('Mozilla/5.0 (','').replace(')',''), writable: false, configurable: false });
    // Object.defineProperty(navigator, 'vendor', { value: 'Google Inc.', writable: false, configurable: false });
    // Object.defineProperty(navigator, 'platform', { value: 'Win32', writable: false, configurable: false }); // Example platform

    // For sites using User-Agent Client Hints (less common for this type of issue, but possible)
    // This is more complex to spoof comprehensively with just a userscript.
    // if (navigator.userAgentData) {
    //     Object.defineProperty(navigator, 'userAgentData', {
    //         value: {
    //             brands: [
    //                 { brand: " Not A;Brand", version: "99" },
    //                 { brand: "Chromium", version: "123" },
    //                 { brand: "Google Chrome", version: "123" }
    //             ],
    //             mobile: false,
    //             platform: "Windows"
    //             // You might need to fill in getHighEntropyValues as well, which is async
    //         },
    //         writable: false,
    //         configurable: false
    //     });
    // }

})();