Order: Grab & Go Placed is a flow-only trigger: it fires when an order containing a Grab & Go item is placed so that Sprwt Emails flows and Klaviyo events can target those purchases, but it has no email template of its own (the customer already receives Order: Create and you receive Admin: Order Create). Because there is nothing to switch on or off, it is hidden from the System Emails page while still being selectable as a flow trigger.