In one of the interviews they said they will aim for more user-friendly file formats that will allow to tweak different aspects of the game (I think they mentioned XML). Is there any further information on this available? I'm thinking about creating a tool for editing these files.

Not yet. But it has to be something that is readable for humans I guess. So it shouldn't matter much if it's XML, YAML or JSON or whatever format they choose. I know that Unity 5 supports JSON serialization. I don't know about any of the other formats. But Unity 5 is scripted with C# and there are tons of stuff in C# which can deal with those data formats.

Edited February 27, 20178 yr by Boeroer