They are just additional texture files with censor, which are loaded instead of the non-censored sprites. The original non-censored sprites are still present on their original texture sheets.
View attachment 45976
Here the textures that needed be uncensored for the demo:
HachinaDemo_Uncensor.zip
You can use BepInEx with Texture Replacer plugin to inject the edited textures, but you'd still need to get rid of the mosaic censor effect on top of it. I tried to use Universal Unity Demosaics plugin (using the DumbRendererDemosaic) but it causes randoms crashes while playing unfortunately... It does work though, but I have no clue why it randomly crashes.