Attribution-NonCommercial-ShareAlike 4.0 International is the general license we use. But at the same time, we have additional terms that allow you to use our projects in some way that general license doesn't, see below:

You are permitted to modify the Midsoul datapack or publicly release modified versions, provided that the following conditions are met:

You must continue to use the full license agreement, including these additional terms; you may impose additional restrictions, but you may not delete or modify any existing restriction clauses.
You must clearly credit the production team in an appropriate location and include a link to the official release channels of Midnight Soul (Bilibili or the GitHub repository).
You must not add any content that may cause misunderstanding, or in any way imply that your work has any direct association with or endorsement from the official Midnight Soul team.
You must not incorporate any non-cosmetic content obtained through paid means, such as additional attack damage, additional abilities, or additional mechanics (including but not limited to terrain mechanics and game mechanics).

You are permitted to modify the Midnight Soul save file or publicly release modified versions, provided that the following conditions are met:

You may not release maps that include terrains created by other creators without further authorization; the copyrights of these terrains remain with their respective creators.
The modified version of Midnight Soul that you release may include original maps marked with "<Original>", but these maps may not be used in any other publicly released map without obtaining authorization.
Authorization for terrains created by other creators can be obtained via the in-game link to their original release pages, and such authorization shall follow the terms specified on those original release pages; authorization for original Midsoul maps can be obtained from the production team.
In addition, the above additional terms for the datapack also apply to the save file.