Using Extended Entity Data to determine the "original" Revit Category

Jeremy shows how you can review a DWG file to determine if the source entities were Text or Labels in Revit.  This principle extends further, as he describes:

The differing TypedValue 11 is consistently -2000300 for a text and -2000280 for a label element.
What does this mean?
Well, is actually quite easy.
On seeing these large negative numbers in this specific range, an experienced Revit developer will quickly suspect built-in category or parameter enumeration values.
You can check what they actually represent in the Visual Studio debugger, by jumping to the definition of these enumerations and searching for the specific values.
Looking back at an ancient blog post on the DWG and DXF export Xdata specification confirms that these numbers do indeed represent the built-in category of the source element and thus can be used to distinguish the two.

via
The Building Coder: DWG Issues and Various Other Updates