ExportPackageOptions.IncludeLibraryAssets

Description

The exported package will include all library assets, ie. the project settings located in the Library folder of the project.

This is useful for exporting an entire project in a single unitypackage:

AssetDatabase.ExportPackage("Assets/", "Entire Project.unitypackage", ExportPackageOptions.Recurse | ExportPackageOptions.IncludeLibraryAssets );