Copying my comment from github (incase it one day gets lost):
We probably don't want to include this port mapping in the example docker-compose as 90% of people would not want it.
This would open up blazegraph to any writing / adding of data.
@RazShutyWMDE Is creating a docker-compose generator for this wikibase stuff based on https://github.com/tarrow/blubber and an option for this port could be added to that.
We could also update the README for the wdqs image stating which ports are exposed internally and that could be exposed externally if the user so chooses.
I think some better documentation of the ports makes the most sense. And I guess this would come under T192792 which has a ports item on the list.