This folder contains the HDF5 header files, which were converted using c2nim. Some of them had to be modified for c2nim to successfully convert them.
The files themselves are not needed, they are here for reference in the future, in case bugs happen due to unwarranted / breaking changes to these header files.
This might quite possibly be the case, due to my lack of understanding of the HDF5 library / desire to get it working in the first place.