Man pages matching name memcached_pool_behavior_set in section 3:

memcached_pool_behavior_set.3.en	debian 10 / libmemcached-dev
memcached_pool_behavior_set.3.en	debian 11 / libmemcached-dev
memcached_pool_behavior_set.3.en	debian 12 / libmemcached-dev