...
While not all that common, the attribute-filter.xml file can leverage property replacement to externalize particular settings. By default, these properties are defined in the idp.properties file. Properties are referenced via a brace syntax (e.g., %{idp.home}
).
The properties which affect the filtering process are names staring with idp.service.attribute.filter
as described here
Schema Name
Elements described in this page and its children are defined by the urn:mace:shibboleth:2.0:afp
namespace, the schema for which can be located at http://shibboleth.net/schema/idp/shibboleth-afp.xsd
...