protected void handleUnmappedAttribute(final Map<String, List<Object>> attributesToRelease, final String attributeName, final Object attributeValue) {
        LOGGER.debug("Found attribute [{}] that is not defined in pattern definitions", attributeName);
        if (excludeUnmappedAttributes) {
            LOGGER.debug("Excluding attribute [{}] given unmatched attributes are to be excluded", attributeName);
        } else {
            LOGGER.debug("Added unmatched attribute [{}] with value(s) [{}]", attributeName, attributeValue);
            attributesToRelease.put(attributeName, CollectionUtils.toCollection(attributeValue, ArrayList.class));
        }
    }
Handle unmapped attribute.

@param attributesToRelease the attributes to release
@param attributeName       the attribute name
@param attributeValue      the attribute value
core/cas-server-core-services-api/src/main/java/org/apereo/cas/services/support/RegisteredServiceMappedRegexAttributeFilter.java