Man pages matching name malloc_usable_size in section 3:

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