What is an .exe file stub?

Question

I'm learning how to obfuscate my assembly using .NET Reactor.

One option is to "Generate a native x86 EXE file stub," which I do not understand its purpose. I import an assembly (e.g. an .exe file) and output an obfuscated .exe file, which is roughly the same size. If I checked "Generate native x86 file stub" the software outputs an .exe file which is much smaller in size (like the .exe is compressed...)

I don't understand what that means. And in the documentation:

.NET Reactor is able to generate a native x86 EXE file stub for your application. This way it is not possible to directly open your protected application in a decompiler. The decompiler recognizes your protected application as a native EXE file.

Why do I want to generate an .exe from a file that is already an .exe?

Answer 1

Though your question was some time ago, I thought I'd share an answer:

Have you ever used a Tool like Reflector, ILSpy or dotPeek? Those tools can be used to generate the source from an managed assembly. If you use that native x86 stub, those tools should tell you "Cannot open unmanaged dll" (or something similar) - according to the developer.