As you can see from the image above the import in Unity is always organized in this way:

• A Root Gameobject containing all objects in the scene
• A Gameobject for each Document of the Revit Project (i.e. Linked Files)
• A Gameobject for each level of this document (plus another gameobject for Elements in Revit that does not appear to have a Level assigned)
• Then a Gameobject for each Category in that level
• Then the list of Elements in the last group. For those elements there are two main types, Elements with a single Geometry (single material) or Elements with multiple geometries (multiple materials)

All geometries are optimized to be statically batched by default.