Remove DLLs from build

I’m building a WebGL project and I can’t seem to get it under 7 MB despite minimal assets.

Currently, dll’s are taking about 50% of he build. I’ve tried everything I can think of to reduce dependencies. “System.” doesn’t appear anywhere in my project except “using System.Collections”, “using System.Collections.Generic”, “System.IEquatable”, and “System.BitConverter.ToInt64”. I’ve cleared every cache I could find and still the following show up as dependencies according to the editor log:

Dependency assembly - Mono.Security.dll
Dependency assembly - System.Core.dll
Dependency assembly - System.dll
Dependency assembly - mscorlib.dll
Dependency assembly - UnityEngine.UI.dll
Dependency assembly - UnityEngine.Networking.dll
Dependency assembly - Assembly-CSharp.dll

Also, MonoDevelop includes references to:

I can remove references to all, but UnityEngine and UnityEngine.UI and it still builds properly. My project has included references to those dlls in the past, but I’ve since removed them.

I should have done this from the beginning, but it turns out that an empty WebGL project includes all the same DLLs and and takes 3 MB all built. I’ll have to look at a new way to reduce my memory pull.