What is Your Day?
Your Day is the execution layer of your Agenda: your day's schedule — your meetings in order — so you can see what's ahead at a glance.
It sits below Needs Attention and shows your calendar events in sequence, with the reminders due that day alongside them — a reminder is due on its day rather than at an hour, because that is what Google Tasks stores. Reminders in Your Day you can complete inline. It's for awareness of what's coming, not a place that interrupts you.
See also: What is the Agenda? · Where do I see what's due?