Man pages matching name pcre2_jit_free_unused_memory in section 3:

pcre2_jit_free_unused_memory.3.en	debian 10 / libpcre2-dev
pcre2_jit_free_unused_memory.3.en	debian 11 / libpcre2-dev
pcre2_jit_free_unused_memory.3.en	debian 12 / libpcre2-dev