Slicer  4.8
Slicer is a multi-platform, free and open source software package for visualization and medical image computing

Widgets → Core Relation

File in Libs/MRML/WidgetsIncludes file in Libs/MRML/Core
qMRMLClipNodeWidget.hvtkMRMLClipModelsNode.h
qMRMLLayoutWidget.hvtkMRMLLayoutNode.h