Complex sentence: He is put on trial again the following day, under new charges brought by the Defarges and one "unnamed other", soon learned to be Dr. Manette, through his account of his imprisonment.
Split into simpler sentences: He is put on trial again the following day, under new charges brought by the Defarges and one "unnamed other". We soon discover that this "other" is Dr. Manette, through his own account of his imprisonment.