Open Leads vs. Todays Leads? What setting makes them such?

Open Leads vs. Todays Leads? What setting makes them such?

What makes a lead Open or Todays Lead in the Predefined Views in the Leads Tab?   There is nothing in the Lead Status field selection in a lead that has in the pulldown menu "open" or "Todays"  Thank you.

Fyi, I think I figured it out.  I went to Reports and saw that Todays Leads relates to Created or Modified Time.  Still need to know what makes an Open Lead?