Very large builds, why?

Hi,

In my games almost everything is made in runtime procedurally but when I build for Mac OSX or Windows, the file size is almost 50MiB.

The scene I add in the build is an empty scene with just a box as floor. I added the pro shaders and I used some of them and also an FPS asset.

To determine what caused the big size, I opened the .app in OSX and found these to be consuming the most space:

sharedassets0.assets ~ 18MiB Executable ~ 12MiB unity default resources ~ 13MiB

Is there any way to remove any of them to reduce the file size?

Thanks.