Slicer  4.13
Slicer is a multi-platform, free and open source software package for visualization and medical image computing

SubjectHierarchyPlugins → SubjectHierarchy Relation

File in Modules/Loadable/Markups/SubjectHierarchyPluginsIncludes file in Modules/Loadable/SubjectHierarchy
qSlicerSubjectHierarchyMarkupsPlugin.hWidgets / qSlicerSubjectHierarchyAbstractPlugin.h