Frontend & browser·The network from the browser
you stopped concatenating every file into one, because the connection now carries dozens of requests at once.
HTTP multiplexing
Also calledHTTP/2, connection reuse, head-of-line blocking
Sending many requests concurrently over a single connection, which removed the six-connection limit that made request count so expensive under HTTP/1.1. It is why sprite sheets and domain sharding became obsolete, and why splitting a bundle into more chunks is now cheap. It does not make requests free: each still has a priority, and TCP-level head-of-line blocking on a lossy connection still stalls the whole stream until HTTP/3.