Man pages matching name secure_getenv in section 3:

secure_getenv.3.de	debian 10 / manpages-de-dev
secure_getenv.3.en	debian 10 / manpages-dev
secure_getenv.3.ja	debian 10 / manpages-ja-dev
secure_getenv.3.pl	debian 10 / manpages-pl-dev
secure_getenv.3.de	debian 11 / manpages-de-dev
secure_getenv.3.en	debian 11 / manpages-dev
secure_getenv.3.fr	debian 11 / manpages-fr-dev
secure_getenv.3.ja	debian 11 / manpages-ja-dev
secure_getenv.3.de	debian 12 / manpages-de-dev
secure_getenv.3.en	debian 12 / manpages-dev
secure_getenv.3.fr	debian 12 / manpages-fr-dev
secure_getenv.3.ja	debian 12 / manpages-ja-dev
secure_getenv.3.ru	debian 12 / manpages-ru-dev