Refund Reasons are a list of short labels (e.g. Damaged, Customer changed mind) that staff pick when refunding meals from the POS Orders screen or the Retail Grab & Go sales refund screen. Those screens show the reason list, an optional Update Stock switch (This will add the item back to stock for further purchase), and record the chosen reason on each refunded meal. Reasons are managed under Settings > Kitchen Settings > Refund Reasons (/admin/refundreasons), which appears when you have both the Retail and Grab & Go modules. The Customer Orders page refund buttons do not ask for a reason.