reconsideration of the Clerk’s order granting appellees’ request to file a supplemental appendix is denied. 1 . Because Datto does not challenge the denial of Rule 60(b)(3) relief on this appeal, we deem that issue waived. See Skretvedt v. E.I. DuPont De Nemours, 372 F.3d 193, 202-03 (3d Cir.2004) ("[A]n issue is waived unless a party raises it in its opening brief, and for those purposes a passing reference to an issue will not suffice to bring that issue before this court.”). In addition, we note that, while the District Court did not specifically address Datto's contention that Rule 60(b)(1) provides a basis for relief because Datto made a "mistake” in accepting the settlement, any such contention is without merit. See Coltec Indus., Inc. v. Hobgood, 280 F.3d 262, 275 (3d Cir.2002) (<HOLDING>). Likewise, Datto's alleged mistaken belief
holding that evaluations submitted after the committees final decision cannot be considered in determining whether the decision was arbitrary and capricious recognizing that the existence of a copy of a decision in a bill file along with numerous references to a decision of the court of appeals in the legislative history indicated that an amendment was made in response to that decision holding that even if partys decision to settle was improvident in hindsight the decision is made and cannot be revisited holding that evidence contrary to an administrators decision does not make the decision arbitrary and capricious so long as a reasonable basis appears for the decision holding that a document is predecisional if it was prepared to assist an agency in arriving at a decision rather than supporting a decision already made