Man pages matching name ptmx in section 4:

ptmx.4.en	debian 10 / manpages
ptmx.4.de	debian 10 / manpages-de
ptmx.4.es	debian 10 / manpages-es
ptmx.4.ja	debian 10 / manpages-ja
ptmx.4.en	debian 11 / manpages
ptmx.4.de	debian 11 / manpages-de
ptmx.4.es	debian 11 / manpages-es
ptmx.4.fr	debian 11 / manpages-fr
ptmx.4.ja	debian 11 / manpages-ja
ptmx.4.en	debian 12 / manpages
ptmx.4.de	debian 12 / manpages-de
ptmx.4.es	debian 12 / manpages-es
ptmx.4.ja	debian 12 / manpages-ja
ptmx.4.ru	debian 12 / manpages-ru