Blender is arguably one of the best tools for developing a wide variety of assets, and glTF is often a good export format for real-time graphics applications given how much of it supports and how extensible it is.
However, handling glTF files with application specific content is still somewhat tricky in Blender, often requiring pretty deep knowledge of both the glTF format and the Blender scripting API.

During this presentation, the basic developer view of the glTF Blender IO add-on is presented with a focus on using it to create custom importer and exporters plugins to extract or embed almost arbitrary data from or into glTF files.