I see this a bit like having .ipynb extension for Jupyter notebooks. if you look inside they are a big fat json, so they could also be called .json but they're not. The benefit is that GitHub, seeing the ipynb extension, creates a preview of that same json file.
If there was a .nrjson or .jnrflow extension, GitHub could do the same with Node-RED flows.
Both formats have something in common: they are visual, so they should be presented visually. My beef against the "one long line of json" is not unheard of so I might be biased.
Also also my editor would be happy since I would map the extenstion to fundamental-mode instead of having it parse a 1.3MB long json string because the json-mode kicks in for .json files.
