I think they are working with multiple manufacturers but probably not Medtronic. Just my guess, as the Medtronic old pumps already do work with the system. Currently Loop works with any CGM data that is uploaded to NightScout, so most people who are using Loop use Dexcom. If the data from Dexcom is approved for dosing decisions (as it is) then I don’t think it’s that much of a leap to approve the algorithm for use with a pump.
Basically Loop takes data from Dexcom (or I guess Libre), then uses the algorithm to make BG predictions and sends commands to the pump via something called a Riley Link. My guess is the plan is to eliminate the Riley Link element and actually find out the pump communication protocols from other companies so that they can have it run on a phone.