Posit Workbench is a strict superset of RStudio Server -- that is, it is a copy of RStudio Server with extra features added. It is occasionally necessary for code supporting Workbench features to exist in the open source version. This is one such case; RStudio Server maintains a user database even in the absence of licensing. It's useful not only to help track usage but to help organizations who migrate from the open-source product to the commercial product.