Attributes — h5py 3.5.0 documentation
https://docs.h5py.org/en/stable/high/attr.htmlAttributes. Attributes are a critical part of what makes HDF5 a “self-describing” format. They are small named pieces of data attached directly to Group and Dataset objects. This is the official way to store metadata in HDF5. Each Group or Dataset has a small proxy object attached to it, at <obj>.attrs. Attributes have the following properties: