Man pages matching name anyevent::xmpp::ext::pubsub in section 3pm:

AnyEvent::XMPP::Ext::Pubsub.3pm.en	debian 10 / libanyevent-xmpp-perl
AnyEvent::XMPP::Ext::Pubsub.3pm.en	debian 11 / libanyevent-xmpp-perl
AnyEvent::XMPP::Ext::Pubsub.3pm.en	debian 12 / libanyevent-xmpp-perl