getCustomCurrencies() {
			return mSettings["currency"];
		}
Gets the custom currencies that have been set via
{@link #.addCustomCurrencies Formatting.addCustomCurrencies} or
{@link #.setCustomCurrencies Formatting.setCustomCurrencies}.
There is a special currency code named "DEFAULT" that is optional. If it is set it is used for all
currencies not contained in the list, otherwise currency digits as defined by the CLDR are used as a
fallback.

@returns {Object<string,module:sap/base/i18n/Formatting.CustomCurrency>|undefined}
  A map with the currency code as key and a custom currency definition containing the number of decimals as
  value; or <code>undefined</code> if there are no custom currencies

@public
@example <caption>A simple example for custom currencies that uses CLDR data but overrides single
  currencies</caption>
{
  "EUR3": {"digits": 3}
  "MYD": {"digits": 4}
}

@example <caption>A simple example for custom currencies that overrides all currency information from the
  CLDR</caption>
{
  "DEFAULT": {"digits": 2},
  "ADP": {"digits": 0},
  ...
  "EUR3": {"digits": 3}
  "MYD": {"digits": 4},
  ...
  "ZWD": {"digits": 0}
}
@since 1.120