Currently, when listing credentials inside a domain using the XML API you receive something like this:

<domainWrapper>
  <credentials>
    <b935f3cc-8a17-4f62-b567-b4e7b7a1d76e>
      <fullName>
        credential-store/Domain Name/b935f3cc-8a17-4f62-b567-b4e7b7a1d76e
      </fullName>
      <typeName>Username with password</typeName>
    </b935f3cc-8a17-4f62-b567-b4e7b7a1d76e>
...

Please include the username and description in the output for each pair, comparable to what is visible for normal users when they are selecting the credentials to use in their jobs. Otherwise, it is hard to automatically do configuration updates for jobs that require authentication.