documentation on custom CMD/ENTRYPOINT

# alpine-slim/Dockerfile
ENTRYPOINT ["/docker-entrypoint.sh"]

EXPOSE 80

STOPSIGNAL SIGQUIT

CMD ["nginx", "-g", "daemon off;"]

# entrypoint/docker-entrypoint.sh
if [ "$1" = "nginx" ] || [ "$1" = "nginx-debug" ]; then
#  code that executes /docker-entrypoint.d/ scripts

so for a custom CMD to actually execute those scripts it has to be on the form

CMD ["foo", "/docker-entrypoint.sh", "nginx", "-g", "daemon off;"]

but there is no such mention on the documentation https://hub.docker.com/_/nginx/

Start by reading alpine-slim/Dockerfile and entrypoint/docker-entrypoint.sh to confirm how custom CMD values interact with the entrypoint. Update the nginx Docker Hub documentation with the required custom CMD form and verify that it explains when /docker-entrypoint.d/ scripts run.