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I'm interested into modifying Chat.Onion software to build an application on my own, I guess it's some type of free software as its source code can be accesed, but on the other hand on its github page I can't see anything that shows its license, I thought that maybe all projects in github were under some standard license but it looks like every person that submits a project can choose one, there doesn't seem to be any way to contact the developers (I even tried to enter its .onion link and I can't access it), I could maybe open an issue in github and contact the author about this, anyway it would be out of place and in any case the author doesn't seem to be answering the issues that have been writthen there.
Is there some way to know the license of this software? Maybe I'm missing something.
Apart from that, in the case it didn't have one, would I be able to freely copy and modify the software as I wished?