Turbolinks Classic is a now-deprecated JavaScript library (largely used in Rails projects) for speeding up navigation by intercepting link clicks and replacing only the <body> and page title instead of reloading the entire page. It avoids recompiling JS and CSS on each navigation, improving perceived performance. Turbolinks makes following links in your web application faster. Instead of letting the browser recompile the JavaScript and CSS between each page change, it keeps the current page instance alive and replaces only the body (or parts of) and the title in the head. Think CGI vs persistent process.