What really surprised me is the use of AGI rather than MAGI.  Maybe they're feeling generous this time.

Timing will also be interesting.  Some people may want to game the system by not filing 2019 until the check arrives, not realizing that it's only an advance refund.  Those who have balances due may decide to wait to make sure the credit will be reflected on their returns but there's no telling whether the IRS will put 1040 update on the back burner (as it will take time) so that checks can get out the door asap.