Included DLLs? What are those?

Questions & Answers
1

I just built my game for testing and looked at the editor log. It said "Included DLLs" and had like 4+ MB of data. That's a lot of space used up there.

Is that the stuff that comes pre-built in with Unity? Or is that something else?

Just want to double check.

2

Yes, those are probably the DLLs for the libraries you used (System.dll etc). If you use System.Xml for example you add 1Mb to the final size afaik, because it includes the whole XML namespace which is huge. And so on. See:

http://unity3d.com/support/documentation/Manual/Reducing%20File%20size.html