Also piping to cat seems redundant but malicious hosts can detect whether the request is getting redirected, using some clever trick, so it’s not.

Just so you know, servers cannot detect piping to any arbitrary process. The trick you're talking about is detecting piping to an interpreter, for the lack of a better term. Piping sleep N to bash is observable behaviour, for example. Piping anything to cat is not.

https://web.archive.org/web/20250622061208/https://www.idontplaydarts.com/2016/04/detecting-curl-pipe-bash-server-side/