describe refunds as discussed

articles/ui/ui.tex

@@ -976,12 +976,15 @@ it has the following key advantages:
 \begin{lstlisting}
 <script src="taler-wallet-lib.js"></script>
 <script>
-  taler.offerRefundFrom("https://myshop/purchase/42/refund", (err) => {
+  // Obtain refund permissions from the merchant backend
+  // ...
+  let refundPermissions = /* ... */;
+  taler.acceptRefunds(refundPermissions, (err) => {
     alert("An error occured while attempting a refund");
   });
 </script>
 \end{lstlisting}
- \caption{Sample JavaScript code to trigger a refund}
+ \caption{Sample JavaScript code to trigger a refund from the merchant's web shop}
   \label{listing:refund}
 \end{figure*}
 
@@ -1000,13 +1003,11 @@ the exchange providers and fee structure, but not the cryptographic
 coins.  Consequently, the major cryptographic advances of Taler are
 invisible to the user.
 
-Taler's refresh protocol~\cite{talercrypto} also allows merchants to
-give refunds to customers. For this, the merchant signs a message
-that the customer's wallet processes (Figure~\ref{listing:refund}) and sends to the exchange in order
-to obtain new coins as a refund.  This
-can even be done with anonymous customers, as refunds are given as
-additional change to the owner of the coins that were originally spent
-to pay for the refunded transaction.
+Taler's refresh protocol~\cite{talercrypto} also allows merchants to give
+refunds to customers. To refund a purchase, the merchant obtains a signed refund permission
+from the exchange, which the customer's wallet processes
+(Figure~\ref{listing:refund}) to obtain new, unlinkable coins as refund.
+This process allows the customer to say anonymous when receiving refunds.
 
 Taler's refresh protocol ensures unlinkability for both change and
 refunds, thereby assuring that the user has key conveniences of other