Man pages matching name net::openid::extensionmessage in section 3pm:

Net::OpenID::ExtensionMessage.3pm.en	debian 10 / libnet-openid-common-perl
Net::OpenID::ExtensionMessage.3pm.en	debian 11 / libnet-openid-common-perl
Net::OpenID::ExtensionMessage.3pm.en	debian 12 / libnet-openid-common-perl