No, that’s the thing. It’s similar, but the Inbox proposal is far more extensive. The idea was first to merge them, but now ByteHamster suggested they could live seperately. So if they live seperately, we need to more clearly define their difference.
As there’s no CI tests in that repo I can’t download a debug build, so I can’t test. But please note that unless there’s agreement by the community, it’s not likely a PR will be accepted. So I would strongly advice you to hold off with actual development until we’re clear on which screens we’ll have, and what they’ll look like exactly. Otherwise you might well be wasting your time 
It’s important to note that the Inbox screen is different from the Home screen. As I don’t know what you’re working on, I can’t really comment on the quote above.