a source I cannot name

This source has never been identified. There are three main possibilities:

1. As implied here, the Scholar knew the source, but withheld the name even from this private diary, in order to protect either the source or himself;
2. The Scholar did not know the source — that is, the document(s) somehow just 'appeared on the doorstep', without attribution;
3. Despite denials elsewhere, the Scholar himself is the source.