Man pages matching name hostname in section 5:

hostname.5.de	debian 10 / manpages-de
hostname.5.zh_CN	debian 10 / manpages-zh
hostname.5.zh_TW	debian 10 / manpages-zh
hostname.5.en	debian 10 / systemd
hostname.5.de	debian 11 / manpages-de
hostname.5.zh_CN	debian 11 / manpages-zh
hostname.5.zh_TW	debian 11 / manpages-zh
hostname.5.en	debian 11 / systemd
hostname.5.de	debian 12 / manpages-de
hostname.5.zh_CN	debian 12 / manpages-zh
hostname.5.zh_TW	debian 12 / manpages-zh
hostname.5.en	debian 12 / systemd