The Stemfie Workbench is an external workbench aimed at implementing a parametric set of parts for the Stemfie project.
The Stenfie workbench is not bundled with the default FreeCAD package, but can easily be installed via the 
Addon Manager. Invoke it from Tools → Addons Manager. The Stemfie workbench code is hosted and developed on github and can also be installed manually by copying it into FreeCAD's MOD directory.
⏵ documentation index > Addons > External_Workbenches > Stemfie Workbench