How to treat initial headhunter outreach as a senior?

Hey guys -

I am a senior with a full-time banking role starting this summer. I've been getting a lot of initial outreach from headhunters asking for a 30-min introductory call.

They often say that these calls are "informal and not an interview" but I wanted to ask how I should really be treating these calls. What types of things do they ask, and how should I prepare? Should they be treated like a real interview? Do they ever ask technical questions during these intro calls, or is it more just trying to get a gauge on what buy-side roles you're interested in?

Any advice would be greatly appreciated