Man pages matching name network_namespaces in section 7:

network_namespaces.7.en	debian 10 / manpages
network_namespaces.7.en	debian 11 / manpages
network_namespaces.7.en	debian 12 / manpages
network_namespaces.7.de	debian 12 / manpages-de
network_namespaces.7.es	debian 12 / manpages-es
network_namespaces.7.fr	debian 12 / manpages-fr
network_namespaces.7.ru	debian 12 / manpages-ru