Man pages matching name rsa_padding_add_pkcs1_type_1 in section 3ssl:

RSA_padding_add_PKCS1_type_1.3ssl.en	debian 10 / libssl-doc
RSA_padding_add_PKCS1_type_1.3ssl.en	debian 11 / libssl-doc
RSA_padding_add_PKCS1_type_1.3ssl.en	debian 12 / libssl-doc