I was at ORD last week. At the beginning of the the H/K concourse there is a small information counter, more like a table with 2 airport staff. There was a sign on this table that mentioned the QR shuttle and I believe it referenced a G gate, maybe G15 or G17, and the operating times. Sorry I cant be more specific but I had looked up this QR bus info before so the sign caught my attention as confirmation that someone knows about a bus. Whether the bus actually exists is another question since this was just a sign at an info table.