Man pages matching name x509_store_ctx_set_verify_cb in section 3ssl:

X509_STORE_CTX_set_verify_cb.3ssl.en	debian 10 / libssl-doc
X509_STORE_CTX_set_verify_cb.3ssl.en	debian 11 / libssl-doc
X509_STORE_CTX_set_verify_cb.3ssl.en	debian 12 / libssl-doc