Unity does not copy non-binary files to build output in standalone mode

Summary

Unity does not copy non-binary files to build output in standalone mode.

Affected files are for examples the lua scripts, plugins.dat, and any relevant file that is not a DLL.

Minimal project and steps to reproduce

Try to play a youtube video in standalone mode.

What is the current bug behavior?

Nothing.

What is the expected correct behavior?

Playing video.

Does it work on other plaforms? Does it work with the official VLC apps?

Yep.

Possible fixes

A few, not sure what's the cleanest yet.

Probably https://docs.unity3d.com/ScriptReference/Build.IPostprocessBuildWithReport.OnPostprocessBuild.html