There is no license file for the overall project.

There is a license file here: https://github.com/KNCarnage/CSharpSynthForUnity2.0/blob/main/Assets/ThirdParty/CSharpSynth/License.txt

But this only covers the original CSharpSynth. I would appreciate if your CSharpSynthForUnity2.0 would use the same license (MIT license)