The two assemblies being compared have different naming categories

Namespace: Autodesk.Revit.DB
Assembly: RevitAPI (in RevitAPI.dll) Version: 2015.0.0.0 (2015.0.0.0)
Since: 2012

Syntax

C#
`public class AssemblyDifferenceNamingCategory : AssemblyDifference`

Visual Basic
`Public Class AssemblyDifferenceNamingCategory _ Inherits AssemblyDifference`

Visual C++
`public ref class AssemblyDifferenceNamingCategory : public AssemblyDifference`

Inheritance Hierarchy

System Object
Autodesk.Revit.DB AssemblyDifference
Autodesk.Revit.DB AssemblyDifferenceNamingCategory