It's not in any standard (e.g. JSON) format. I made it up as a way for someone to easily comprehend and amend. The project file is only used for the initial loading of default key mappings. Once that's done, any re-mapping of keys is saved/loaded as a JSON array in webstorage.
You can always use your own method of formatting data as long as your app knows how to read it. However, it's oftentimes more convenient to use a standardized format.