The openscad-MCAD package claims to use /usr/share/openscad/libraries/MCAD/boxes.scad as the upstream, but doesn't have changes that were done years ago in MCAD (not an active project). Reproducible: Always Steps to Reproduce: Install MCAD, look at MCAD modules such as boxes (roundedCube doesn't exist) and see it doesn't even get close to upstream. Expected Results: Match upstream unless there are platform specific features (wouldn't be the case of MCAD).
The openscad-MCAD package comes from the openscad upstream tarball. As of today, we have openscad 2021.01 which is the latest released openscad version.