Man pages matching name environ in section 5:

environ.5.es	debian 10 / manpages-es
environ.5.pt	debian 10 / manpages-pt
environ.5.zh_CN	debian 10 / manpages-zh
environ.5.zh_TW	debian 10 / manpages-zh
environ.5.pt	debian 11 / manpages-pt
environ.5.zh_CN	debian 11 / manpages-zh
environ.5.zh_TW	debian 11 / manpages-zh
environ.5.zh_CN	debian 12 / manpages-zh
environ.5.zh_TW	debian 12 / manpages-zh