You can determine if a ticket is refundable or not under the 'Flexibility' section of the ticket details before completing the payment. If it is marked as "Non-refundable," it means the flight cannot be refunded. However, if there is a cancellation fee mentioned (e.g., {currency: XXX}), it indicates that the flight can be refunded with the deduction of the specified cancellation fee.
For more detailed information, you can tap on the 'Baggage and policy details' button.