How to make "/" page something other than "/index.html" in static website?

Glitch Help
3

Static server serves XHTML with correct content-type:

printf 'GET /index.xhtml HTTP/1.0\r\nhost:gdccdated.glitch.me\r\nuser-agent:asdf\r\n\r\n' | nc gdccdated.glitch.me 80 | grep -i content-type

outputs

Content-Type: application/xhtml+xml

I wanted to ask if it’s possible to make / page not index.html like index.svg or index.png or index.xhtml.

I use XHTML because it errors when invalid instead of silently doing something weird.

Feature request: custom index file in static websites