203 Non-Authoritative Information

Here you go, but I got it from some other guy.

What it properly means

The returned metadata is not exactly what the origin server has; it came from a local or third-party copy. Mostly used by mirrors and transforming proxies.

Class: 2xx Successful: here you go
Defined in: RFC 9110, section 15.3.4

Get one yourself

This endpoint really answers with 203. Point your client at it and see what it does.

curl -i https://httpcodes.dev/api/203