Code concatenation combines multiple code files into one file for delivery. Instead of requesting each file separately while rendering a page, the browser makes one request, which can improve load times and overall site performance. section 5.1.2
WP Rocket example
WP Rocket concatenates a site's page files as part of its optimization features. The technique works alongside caching and code minification: minification makes files smaller, while concatenation reduces the number of files the browser must request. section 5.1.2
