This is docker container with wine-staging installed. See http://wine-staging.com/ for details.
Xvfb is installed if you need to run something with GUI. Prepend your commands with xvfb-run to use it. Since xvfb-run forks the real Xvfb binary, tini is used as an entrypoint, otherwise xvfb-run hangs.
If you want to run multiple wine processes with Xvfb, wrap then in one Xvfb call instead of spawning multiple Xvfb instances:
xvfb-run sh -c "\
wine foo.exe && \
wine bar.exe && \
wineserver -w"