Amex just sent out an email to merchants about the upcoming Shop Small, the terms read as follows, unclear what the spending requirement will be yet
From June 29 – August 22, 2021, eligible Card Members will receive a statement credit of up to $10, for eligible purchases made at a business location on the Shop Small Map, located here, or the Online Directory, located here, with an enrolled Card. Enrollment limited. The Amex Offer is only targeted to select Card Members and the Offer is available for varying and limited periods of time and are subject to change.