It depends on the team. I applied for two positions and had two interviews, one for each. The interview for one team was heavily on React, while the other one was resume-based.
There were trivial React questions and a question about the most difficult tech task you have ever tackled.
The following metrics were computed from 3 interview experiences for the 1Password Developer Intern role.
1Password's interview process for their Developer Intern roles is fairly selective, failing a large portion of engineers who go through it.
Candidates reported having very good feelings for 1Password's Developer Intern interview process.