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This xsi:type is defined by the urn:mace:shibboleth:2.0:resolver schema3 3.3, which is located at http://shibboleth.net/schema/idp/shibboleth-attribute-resolver.xsd.
Prior to V3.3 supplied plugins were defined by a schema type (xsi:type) in the the urn:mace:shibboleth:2.0:resolver:ad namespace, the schema , for which is located at http://shibboleth.net/schema/idp/shibboleth-attribute-resolver-ad.xsd. This This is still supported, but every element or type in the urn:mace:shibboleth:2.0:resolver:ad schema has namespace has an equivalently named (but not necessarily identical) version in the the urn:mace:shibboleth:2.0:resolver schema namespace. The The use of the the urn:mace:shibboleth:2.0:resolver schema resolver namespace also allows a relaxation of the ordering requirements of sub elements and so a more natural order can be applied. Note that versions earlier than 3.3 are no longer supported and you should look to upgrade at the soonest opportunitychild elements to reduce strictness.
Attributes
Any of the common attributes can be specified. Note that this attribute definition does not require a sourceAttributeID attribute a sourceAttributeID attribute since the information is not resolved from an input attribute. If one is supplied, it is ignored.
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