Lean idle. Rich cruise.

mopowers said
Is this for 100% gasoline, or E15 mix? Or does it even matter?

Good question. I see E10 or even E15 not make a difference in AFR readings.

Sometimes I use Lambda instead, as it doesn't care what the fuel is. But it's not as popular as A/F ratio but it does eliminate fuel choice issues.

To add to what Andy said above, not every gauge reads the same. So tuning to a specific number isn't always a good choice.