For a detailted explanation check out the Spree Guides - Abandoned Carts Endpoint.

• Saves the cart (number, whole payload, last_activity_at and abandoned_at fields) to MongoDB

• Finds a cart that matches the new order number and removes it from the database

• Polls for carts that have been abandoned and generates cart:abandoned messages
• Uses abandonment_period_hours parameter to determine which carts should be considered as abandoned.