Everything on Resources folder goes to the build?

I just want clarification, my project is aways structured like this:

    Resources
      ->Models
      ->Prefabs
      ->Audio
      ->Etc

Everything is aways under the Resources, but now reviewing the documentation it says:

Resource Folders are collections of assets that are included in the built Unity player, but are not necessarily linked to any GameObject in the Inspector.

So, even if the asset is not used, just being under Resources will make it in to the build?

Resources are always included, so if you’re trying to save space in output, you will HAVE to move them out of a Resources directory.

But if you happen to tag your GameObject as “EditorOnly”, it will not be included along with its non-Resource dependencies.

The other way which may or may not be able to exclude files (I don’t think you can), is to write your own Debug class. You can stop it from working outside Unity by using a check:

if(Application.isEditor)

Just use that condition everywhere in your class to stop it from running outside of the editor, on client machines.

Hope this helps

SOURCE : Can I exclude specific assets in Assets/Resources from the build? - Questions & Answers - Unity Discussions