Man pages matching name sigmask in section 3:

sigmask.3.en	debian 10 / manpages-dev
sigmask.3.ja	debian 10 / manpages-ja-dev
sigmask.3.en	debian 11 / manpages-dev
sigmask.3.fr	debian 11 / manpages-fr-dev
sigmask.3.ja	debian 11 / manpages-ja-dev
sigmask.3.en	debian 12 / manpages-dev
sigmask.3.fr	debian 12 / manpages-fr-dev
sigmask.3.ja	debian 12 / manpages-ja-dev
sigmask.3.ru	debian 12 / manpages-ru-dev