Man pages matching name x509_store_set_verify_cb_func in section 3ssl:

X509_STORE_set_verify_cb_func.3ssl.en	debian 10 / libssl-doc
X509_STORE_set_verify_cb_func.3ssl.en	debian 11 / libssl-doc
X509_STORE_set_verify_cb_func.3ssl.en	debian 12 / libssl-doc