Where's the new chest?
The chest is called "tele-provider buffer chest". Its recipe is enabled by researching "logistic system" (the chest reacts to logistic requests so it doesn't make much sense to unlock it immediately).

How does it work?
Like a logistic robot it fulfills open logistic requests when it has the necessary items in its inventory - supply areas (from roboports) don't matter. If available, "request from buffer chests" has to be activated on requesting entities (that's intended).