606 Warnings
If the U.S. Copyright Office determines that the deposit copy(ies) for an otherwise registrable work include some material that constitutes uncopyrightable subject matter, the Office may register the claim without corresponding with the applicant. However, the Office may send the applicant a written communication warning that the registration does not extend to the uncopyrightable subject matter. Communications will be sent to the person specified in the Correspondent field/space of the application (or other designated party, if any). The registration specialist will place a copy of the communication in the registration record, and the certificate of registration and the online public record will indicate the presence of correspondence in the file.
Warnings are intended to put the applicant, the claimant, the courts, and the general public on notice that the registration does not necessarily cover every element of the work. They may also indicate that the Office did not necessarily examine each element of the work for copyrightable authorship. The absence of a warning letter does not necessarily mean that every aspect of the work is copyrightable.