<init:RequestInitiator xmlns:init="urn:oasis:names:tc:SAML:profiles:SSO:request-init" Binding="urn:oasis:names:tc:SAML:profiles:SSO:request-init" Location="https://simplesamlphp.org/some/endpoint" ResponseLocation="https://simplesamlphp.org/other/endpoint" xmlns:test="urn:x-simplesamlphp:namespace" test:attr="value">
  <some:Ext xmlns:some="urn:mace:some:metadata:1.0">SomeExtension</some:Ext>
</init:RequestInitiator>