KiCad is a open source software limited to Printed Circuit Design. A wide range of printed circuit board libraries as well as board layouts are available for it in a free license.
The KiCad format can be used in any way by the LayoutEditor. The schematic and board files can be loaded as well the library can be used as component libraries. The older and the newer KiCad format is supported. Also inside the EditComponent dialog in the SchematicEditor can import parts from the MOD file format. To do so just press the import button within this dialog and choose a library file and afterwards a component of this library. All layers will be converted to the default PCBLayerSetup. The PCB file format design rules will be used. To perform an import simply open a the file with the OpenFile feature. Don't use this import feature without additional validation! An export to the KiCad format is not supported.