Rajat Singh

cc @liranmauda I've started to look into it. So, instead of `unknown-flag` error, the error should be something like `unknown backingstore name type`.If I understood it correctly?.

@akshayjshah I will be working on this. Is there something I need to keep in mind before starting out?

I will update the diagram, thanks for pointing out @kbumsik

cc @mffap @kbumsik please let me know and I will raise a PR.