Man pages matching name i2d_re_x509_tbs in section 3ssl:

i2d_re_X509_tbs.3ssl.en	debian 10 / libssl-doc
i2d_re_X509_tbs.3ssl.en	debian 11 / libssl-doc
i2d_re_X509_tbs.3ssl.en	debian 12 / libssl-doc