This package used to contain the content of the org.osgi.service.log package, which is also provided the org.eclipse.osgi system-bundle.
In order to avoid duplication the content of this package was deleted.
For compatibility reasons the Export of this package has to stay (consumers could require this bundle and then use classes from this package).
And if this package is exported in the MANIFEST.MF it must not be empty, otherwise PDE complains.
This is why this note exists.