Man pages matching name html::mason::psgihandler in section 3pm:

HTML::Mason::PSGIHandler.3pm.en	debian 10 / libhtml-mason-psgihandler-perl
HTML::Mason::PSGIHandler.3pm.en	debian 11 / libhtml-mason-psgihandler-perl
HTML::Mason::PSGIHandler.3pm.en	debian 12 / libhtml-mason-psgihandler-perl