The difference is in handling though. If a config file runs into a BOM, it's likely to tell you on which column and row (0,1) it broke. Same when you compile something. Or it may even recognise the BOM and handle it transparently.

PHP does something different. It outputs it early and when you try to send a header it tells you that's too late. That error is in no way helpful to you at that point unless you already know about this issue, and it won't even help you figure out which file was affected. That part is specific to PHP.

I'm not familiar with Lua pages, but all I can find uses a http / fastcgi server with explicit routing. ASP classic has its own terrible ideas and it's close to death now - 2025 is the last year MS committed to support it, so I don't really think of it as an interesting language anymore.