What is replacegooglecdn?

ReplaceGoogleCDN is a browser extension for Chrome, Firefox, and Edge that automatically redirects requests for Google-hosted web resources to alternative servers located in China. The problem it solves is specific to internet users in China: many websites load JavaScript libraries, fonts, and other assets from Google's content delivery network, but those Google servers are blocked in China, which means pages either load very slowly or break entirely while waiting for resources that will never arrive. The extension works by intercepting network requests in the browser before they go out, and swapping the destination address. For example, a request to Google's font service gets redirected to a Chinese mirror of the same fonts. A JavaScript library that a site loads from Google gets fetched from a faster domestic server instead. The extension handles around 16 different Google-served resources including common libraries like jQuery and Bootstrap, the reCAPTCHA verification widget, Google Fonts, and developer documentation sites. Most of the redirects are turned on by default. A few optional ones, like redirecting jsDelivr or cdnjs, can be toggled through the extension's settings page, which you open by double-clicking the extension icon. The README is written in Chinese and includes a performance comparison showing the before-and-after load times for various resources on a site like Stack Overflow. In one example, a jQuery file that stalled completely from the Google server loaded in 95 milliseconds from the replacement server. The extension is available in the Chrome Web Store, Firefox Add-ons, and the Edge Add-ons store. It can also be installed manually from source by loading it as an unpacked developer extension.