Mortal is a free software provided under the GNU Affero General Public License.
Mortal was not born in a company or lab, but was essentially made by an individual developer out of pure interest. Writing the code and training the model has cost me far more time and money than I anticipated for a hobby. It would be my pleasure if you would like to honor my efforts.
My Tenhou screen name is
二宮蘭子. You could transfer premium days to me at https://tenhou.net/reg/transfer.cgi.