Compare Ethnic Employees of the Library of Congress v. Boorstin, 751 F.2d 1405, 1416 n.15 (D.C. Cir. 1985) (“the Library [of Congress] is not an agency under the Administrative Procedure Act”), with Intercollegiate Broadcasting System, Inc. v. Copyright Royalty Board, 684 F.3d 1332, 1341-1342 (D.C. Cir. 2012) (the Royalty Judges