The Supreme Court has established a briefing schedule in the Seila Law case, which presents the question whether limitations on presidential removal of the director of the CFPB render the agency's structure unconstitutional. The schedule was jointly proposed by the attorneys representing Seila Law (which challenged an agency enforcement action on the ground that limits on removal of the CFPB director violate separation of powers) and the CFPB (which now agrees with the Department of Justice that the removal provision is unconstitutional), and by Paul Clement (who is the Court-appointed amicus curiae tasked with defending the law).
Under the schedule, Seila Law and the CFPB will both file their briefs on December 9, 2019, and Clement will file on January 15, 2020. The schedule allows each side about one more week than it would have under the default time periods in the Court's rules.
Interestingly, although the Court added a second question to the case (whether the statutory provision regarding removal of the CFPB director can be severed from the rest of the Dodd-Frank law if it is unconstitutional), and the CFPB has continued to support severance in other pending cases on the issue while Seila Law will presumably oppose it, the schedule has their briefs due simultaneously. That means that if they do in fact disagree on severability, the only chance the briefs will have to address the other sides' arguments on that point will be in their replies, which will presumably be devoted mostly to replying to Clement's arguments in support of the statute's constitutionality.
Under the Court's rules, amicus briefs are generally due one week after the principal brief of the party they support.