what's relying-party bean attribute "c:_0"?

[Clayton]

Can someone explain what "_0" is in this part of this comment from my
relying-party.xml file?

    <!-- NOTE: these example.org constants are examples and are not
suitable for real use. 
    <bean id="MFASAML2Principal"
parent="shibboleth.SAML2AuthnContextClassRef"
c:classRef="https://example.org/shibboleth/ac/classes/mfa" />
    <bean id="MFASAML1Principal"
parent="shibboleth.SAML1AuthenticationMethod"
        c:_0="http://example.org/ac/classes/mfa" />
    -->


Also, why define MFAPrincipal beans for both SAML1 & SAML2?
The example from [
https://wiki.shibboleth.net/confluence/display/IDP30/MultiFactorAuthnConfiguration
]the MFA config page defines just the one. (I assume that page is about
relying-party.xml - I don't see that explictly stated there)


Thanks in advance!

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://shibboleth.net/pipermail/users/attachments/20180627/b9b78b61/attachment.html>