Man pages matching name lwp::protocol::psgi in section 3pm:

LWP::Protocol::PSGI.3pm.en	debian 10 / liblwp-protocol-psgi-perl
LWP::Protocol::PSGI.3pm.en	debian 11 / liblwp-protocol-psgi-perl
LWP::Protocol::PSGI.3pm.en	debian 12 / liblwp-protocol-psgi-perl