What are some good interview questions that a junior or intermediate dev could ask a senior?

Is this some "I want to ask something smart so I get the job" question?

@k0pernikus No, this is a mid-level dev on a tiny team (who has up until now been doing all the heavy lifting) finally getting a chance to bring on a more senior resource, and who wants to get someone who knows what they're doing and can be a good mentor to the rest of the team.

A/S/L?

How to avoid hair loss 😭