Here is the petition in Treppa v. Hengle:

Appendix

Treppa Application for Stay

Hengle Opposition

Reply

Questions presented:

1. Whether a court can invalidate an agreement to have an arbitrator resolve questions of arbitrability (a “delegation clause”) based on the court’s interpretation of a separate choice-of-law provision.
2. Whether sovereign immunity bars private plaintiffs from suing tribal government officials, in their official
   capacities, for alleged violations of state law

Lower court materials here.

Here is the petition in a related case, Asner v. Hengle:

Question presented:

Can a federal court refuse to enforce the delegation clause of an arbitration agreement on the ground that a choice-of-law provision applicable to the arbitration agreement as a whole prospectively waives federal rights?