[Request]: nginx $host variable explanation is unclear about HTTP/2,3 behaviour

What would you like the documentation team to work on?

https://nginx.org/en/docs/http/ngx_http_core_module.html#var_host is explained thus:

in this order of precedence: host name from the request line, or host name from the “Host” request header field, or the server name matching a request

Ref: https://github.com/nginx/nginx.org/blob/main/xml/en/docs/http/ngx_http_core_module.xml#L3189

As HTTP/3 does not have a conventional request line or request headers, I am unsure if the HTTP/2 or HTTP/3 :authority field will be used to populate $host.

Additional clarity here would help to avoid people using $http_host in dangerous/unpredictable ways.

Which product or products does this request relate to?

Other

Who is the person directly responsible for initiating this request?

@lcrilly

Is this request part of a larger initiative or project?

No

Are there important constraints for this request?

No

Does this request have a due date?

No

Any additional information

No response