head of an agency
(1) For purposes of this subsection— (A) the term “head of an agency” means— (i) the head of an Executive agency, other than the Department of Defense or the Government Accountability Office; (ii) the head of the United States Postal Service; (iii) the Director of the Administrative Office of the United States Courts, with respect to employees of the judicial branch; and (iv) any employing authority described under subsection (k)(2), other than the Government Accountability Office; and (B) the term “limited time appointee” means an annuitant appointed under a temporary appointment limited to 1 year or less.