(a) The Director of the Federal Register may order the preparation and publication of indexes, digests, and similar guides, based on laws, Presidential documents, regulatory documents, and notice materials published by the Office, which will serve users of the Federal Register. Indexes, digests, and similar guides will be published yearly or at other intervals as necessary to keep them current and useful.

(b) Each index, digest, and guide is considered to be a special edition of the Federal Register whenever the public need requires special printing or special binding in substantial numbers.