Optional[Dict[str, Union[str, Any]]],
            Doc(
                """
                A dictionary with the contact information for the exposed API.

                It can contain several fields.

                * `name`: (`str`) The name of the contact person/organization.
                * `url`: (`str`) A URL pointing to the contact information. MUST be in
                    the format of a URL.

 * ways similar to {@link FluentFuture}s:
 *
 * <ul>
 *   <li>by transforming the value from a successful input step,
 *   <li>by catching the exception from a failed input step, or
 *   <li>by combining the results of several input steps.
 * </ul>
 *
 * Each derivation can capture the next value or any intermediate objects for later closing.
 *
 * <p>A step can be the input to at most one derived step. Once you transform its value, catch its

<code>'ä'</code> holds two bytes (<code>0xc3</code> <code>0xa4</code>) representing
a literal <code>a</code>-dieresis, U+00E4, value <code>0xe4</code>.
</p>

<p>
Several backslash escapes allow arbitrary values to be encoded as
ASCII text.  There are four ways to represent the integer value
as a numeric constant: <code>\x</code> followed by exactly two hexadecimal

-->

<!--
  | Improvements:
  |
  | o add specification element to a field, this would be more a technical description of
  |   what is allowed in the field.
  |
  | o validators: there could be several levels of validation. Simple type validation could
  |   be done with a regex, but we need inter-field validation and rules which could be
  |   dealt with by something like drools.
  |