Continuing the discussion from IFC import to SketchUp:
No IFC file types listed on page:
No instructions nor benefits or limitations given in the Help Center.
(At least no right column section link.)
I did find a general paragraph on IFC import / export on the Classifying Objects page:
You can export the objects into other formats or programs. When you export SketchUp objects, they can contain all kinds of higher-order representations of things. For example, if your project workflows use BIM, you can export objects classified using the IFC 2x3 schema from SketchUp into the open BIM data exchange standard, IFC. (IFC stands for Industry Foundation Classes, an open data model standard for building information.) Rendering applications can use these attributes, such as material type and light sources, to simulate a scene. SketchUp’s APIs expose all the additional data that developers need to make rich importers and exporters from just about any information modeling format.
I think IFC import export deserves it's own page(s) listing file types, specification versions, limitations, drawbacks, etc.