FreeCAD 0.20 features hundreds of enhancements and bug fixes : the new “Preference Pack” Addon type allows packaging and distribution of any of the settings in a FreeCAD configuration file. The driving application for the new feature was the need to set font and color information along with setting the overall user interface stylesheet, enabling a complete, self-contained “theme” to be applied in a single button click.
FreeCAD includes the ability to easily save a new Preference Pack storing various appearance settings into a single package that can be applied (and reapplied) any time. Advanced users can customize the Pack by adding any other settings that can be added to a FreeCAD configuration file, and developers can create custom packs designed for distribution via the Addon Manager.
Read the original announcement and get help with the feature in the FreeCAD forums discussion . Technical information about Preference Packs can be found on the FreeCAD Preference Packs wiki page .