What kind of questions are asked in a Co-founder interview round?

Yesterday at 5 PM, I had an interview for an Automation Testing role. It was a technical interview where they asked me some aptitude questions and had a 1-hour coding round.

Fortunately, I got selected! Today at 9:30 PM, I’ll be having a Co-founder round, but I’m not sure what to expect from it.

Does anyone have an idea about what this interview might be about or what kind of questions are typically asked in a Co-founder round?