We use the docker images for testing our plugins, using qgis_setup.sh like documented here: https://github.com/qgis/QGIS/tree/master/.docker#running-tests-for-a-python-plugin

But... the Dockerfile in there isn't used anymore as far as I can see and it has been replaced by the one in this qgis-docker repository. And the install method here misses the test setup scripts provided by the older docker images:

$ docker run --rm -it docker.io/qgis/qgis:release-3_16 which qgis_setup.sh
/usr/bin/qgis_setup.sh
$ docker run --rm -it docker.io/qgis/qgis:3.38 qgis_setup.sh
docker: Error response from daemon .... : "qgis_setup.sh": executable file not found in $PATH: unknown.

So: is this a bug? Or intended behaviour? Is there a different docker I should be using?
See related issue in the qgis repo: qgis/QGIS#57931