As luck would have it, the case dealt with jurisdictional issues in federal employee "mixed" cases. As someone who represented a USPS employee in such a case, I can assure you that the system is setup to be an unnecessarily convoluted mess with procedural traps for the employee every step of the way. The case at SCOTUS yesterday was Perry v. MSPB (SCOTUSblog page), and SCOTUSblog identifies the issue as:
Whether a Merit Systems Protection Board decision disposing of a “mixed” case (one which challenges certain adverse employment actions and also involves a claim under the federal anti-discrimination laws) on jurisdictional grounds is subject to judicial review in district court or in the U.S. Court of Appeals for the Federal Circuit.Ahh, clear as mud, right? In any event, here is the SCOTUS transcript, with Justice Gorsuch debuting on page 10 (spoiler alert - this exchanges goes on for a several pages, with the highlight perhaps being Justice Gorsuch apologizing for "taking up so much time"... and then asking another question).
I wouldn't read too much into his questions. I can offer two observations though: (1) He seemed to focus on statutory language (no surprise); and (2) He was pretty talkative (closer to Scalia than Thomas on the participation spectrum).