Developing and maintaining a feature model is a tedious process and gets increasingly difficult with regard to large product lines consisting of thousands of features and constraints. In addition, these large-scale feature models typically involve several stakeholders from different domains during development and maintenance. We aim at supporting such stakeholders by deriving and explaining implicit constraints for partial feature models. A partial feature model can either be a submodel of a feature model representing the full product line or a specific feature model in a set of interrelated models. For every implicit constraint, we generate an explanation exposing which other model parts and constraints interfere with the partial model of interest. Thus, stakeholders are only confronted with a small part of the feature model reducing the complexity while preserving the necessary information about dependencies. Our approach is implemented in the open-source framework FeatureIDE.