Asset id to which to save the new additional.
Example:00000000-0000-0000-0000-000000000000
The upload id of the file.
Example:T3.fS5.5HPhtYFtm2b_.e7wVe910tL5XQutKw1jkMqlP5cPQVyZkOZxZ9lJiGUk4FIw6M0CFZ3xogTWrm.GPI2p2CaglQcAS5aH37zT_vHJnbtkebYbheXIQc_.M_6hM