The plugin remains etag and last-modified header from upstream about nginx-sxg-module HOT 1 CLOSED

Thanks for the detailed report with clear diagram! I think this would be a good initial fix, though the FR can be generalized further. The module should remove or replace all outer response headers that have been copied into the SXG as inner headers.

The outer response should include whatever headers are necessary for a response. I think the minimum is:

Date: <current time>
Content-Type: application/signed-exchange;v=b3
X-Content-Type-Options: nosniff

Other ones that are optional and dependent on the situation:

Vary: Accept                # publisher should set this in their nginx config
Transfer-Encoding: chunked  # dunno how this interacts with nginx modules
Connection: keep-alive      # ditto

from nginx-sxg-module.