That's what we call an object-oriented design – a tale of two classes

That's what we call software engineering and object-oriented design - a tale of two classes from the same project cooked by Microsoft:

class ProjectNode 6076 lines (5116 sloc) 274.992 kB

https://github.com/Microsoft/nodejstools/blob/master/Common/Product/SharedProject/ProjectNode.cs

class ProjectTypeDefinition 30 lines (27 sloc) 1.388 kB

https://github.com/Microsoft/nodejstools/blob/master/Common/Product/SharedProject/ProjectTypeDefinition.cs

Two extremes in the same project, sitting side-by-side in the same folder on a disk. Can't imagine a valid reason for such abominations to exist. Anyway, we have the R# nowadays to simplify the refactoring.