There’s a reason they do that: Files can get big

Oh, boy. Wouldn’t it be great if servers had a way to discover the size of the files on their storage without having to read them?

adding various code highlighting and interactivity costs performance

Somebody, quick, there’s work to be done on language theory so that we learn how to do those things with a cost just proportional to the file size!

(No way! Who is that Chomsky guy you keep telling me about?)