This is a sample docker-compose override file that contains some configuration needed for local development of some Structured Data extensions. Note that this may quickly become outdated when updates are made to mediawiki-docker, so you should check the DEVELOPERS.md file in core to make sure your docker-compose.override.yml file is up-to-date.

docker-compose.override.yml

#
# docker-compose override file for Structured Data projects.
# See https://www.mediawiki.org/wiki/MediaWiki-Docker
#
version: '3.7'
services:
  # These lines ensure file ownership is set to your host user/group
  mediawiki:
    user: "${MW_DOCKER_UID}:${MW_DOCKER_GID}"
    # Linux users only: this extra_hosts section is necessary for Xdebug:
    extra_hosts:
      - "host.docker.internal:host-gateway"
  mediawiki-web:
    user: "${MW_DOCKER_UID}:${MW_DOCKER_GID}"
  mediawiki-jobrunner:
    user: "${MW_DOCKER_UID}:${MW_DOCKER_GID}"
  elasticsearch:
    image: docker-registry.wikimedia.org/dev/stretch-elasticsearch:0.1.0
    volumes:
      - esdata:/usr/share/elasticsearch/data
    environment:
      - discovery.type=single-node
    ports:
      - 9200:9200
      - 9300:9300
volumes:
  esdata:
    driver: local

This override file seems to contain a lot of information that is in the main docker-compose file (services mediawiki and mediawiki-jobrunner). Those are probably not necessary to have here. If you're not using the mediawiki-docker compose file in the core directory, then this override file may need updating for the newest version of our images. See the changes here: mediawiki-docker: https://gerrit.wikimedia.org/r/c/mediawiki/core/+/630988

Basically, since php and apache were split into two containers, there is a new container called mediawiki-web, which was added to the the docker-compose.yml

Linux users will need to add the following to their docker-compose.override.yml:

mediawiki:
    # On Linux, these lines ensure file ownership is set to your host user/group
    user: "${MW_DOCKER_UID}:${MW_DOCKER_GID}"
mediawiki-web:
    user: "${MW_DOCKER_UID}:${MW_DOCKER_GID}"

@rakugama you're right! I've been meaning to update this file for a while to remove the duplicate lines and a few things that aren't needed anymore since mediawiki-docker has been updated.