Docker: using nginx-unprivileged as base results in expose arg changing and making Traefik not work out of the box

[samip5]

Steps to reproduce

1. Deploy Traefik
2. Deploy element-web
3. See that Element Web returns bad gateway, and see in Traefik dashboard that it had picked 8080 port instead of 80.

Outcome

What did you expect?

I would have expected it to work out of the box

What happened instead?

I got an error for bad gateway

Operating system

No response

Browser information

No response

URL for webapp

No response

Application version

v1.11.10

Homeserver

No response

Will you send logs?

No

More information

By default, Traefik uses the first exposed port of a container.

[samip5]

Bug introduced by #29353

[t3chguy]

As per #29729 we cannot override the EXPOSE in the base image and for security do not wish to roll our own unprivileged image. Docker has no way to specify EXPOSE based on runtime environment variables. If you wish to also add an EXPOSE 8080 for correctness be my guest but I don't think that will help Traefik's heuristic. We don't claim Traefik support at any point so closing this issue as a wont fix.