We have found one software suitable in our database for this conversion.
FreeCAD supports the STL format (Streolithography for 3D printers) and can import it and further save in FreeCAD's own .fscstd drawings, which will essentially achieve stl to fcstd conversion. This works best with STL models that contain single entity and files that contain 3D data split to several parts may not be imported properly.
Updated: April 19, 2022
STL
Files with stl extension can be mainly found as stereolithography files for 3D printers. Used in many CAD programs as output format for models and prototypes that could be printed in stereolithography devices.
FCSTD
An fcstd file extension is related to the FreeCAD, a parametric 3D modeling software for Windows, Mac, Linux. An fcstd file stores drawing.