EditPolicies are GEF specific; we recommend you read some GEF documentation before playing with these classes. See DevDocEditPolicies to learn more about them.
This package contains Component EditPolicies. Do not get confused; the component does not refer to URN components but rather to a GEF concept. The main behaviour is to return a command when the delete action is executed. The most interesting class in the package is the PathNodeComponentEditPolicy which decides which command to execute, given the selected PathNode.