All the files in that leak pack are in cvs (some version control system) format, there is also a git version of them uploaded by someone else who extracted and repacked the data, i am working on the files to understand the game engine more which helps making the WL4Editor better.
Since the data looks like iQue dev files, so we cannot find code file for everything(Nintendo didn't directly give iQue company the source code but compiled most of them, only left the code which iQue need to translate all the materials into Chinese version). And the most interesting thing is that they have debug symbols in the compiled code file which makes it much easier to reverse engeneering most of the compiled o file.
Oh, another things i think people here will be interested is that, they use assembly and C code (compiled by gnu tool) to develop all those games.
I heard people said those leaks are made by someone arrested in Jan this year, so perhaps it is not something leaked by the iQue company.