From the U.S. Copyright Office/Library of Congress:

On December 12, 2014, the Copyright Office published a Notice of Proposed Rulemaking initiating three rounds of public comment on exemptions that have been proposed in the sixth triennial rulemaking proceeding under the Digital Millennium Copyright Act (“DMCA”), 17 U.S.C. 1201. Section 1201 provides that the Librarian of Congress, upon the recommendation of the Register of Copyrights, may exempt certain classes of works from the prohibition against circumvention of technological measures that control access to copyrighted works.

The Office has posted the first round of comments – from parties who support the adoption of a proposed exemption, as well as parties that neither support nor oppose an exemption but seek to share pertinent information about a proposal.