The company referred to the charger in a support document that was quickly pulled, reports 9to5Mac. Here's what the document said...
Use the Apple 35W Dual USB-C Port Power Adapter and a USB-C cable (not included) to charge your device. Connect a USB-C cable to either port on the power adapter, extend the electrical prongs (if necessary), then plug the power adapter firmly into the power outlet. Ensure the power outlet is easily accessible for disconnecting. Connect the other end of the cable to your device.
Apple doesn't sell a 35W charger or a dual charger; however, the company does have a 30W USB-C charger that is available to purchase now for $49.
According to the document, the dual charger supports Power Delivery (PD) technology.
Input: 100–240V /1.0A
(USB PD) Output 1 or 2: 5VDC/3A or 9VDC/3A or 15VDC/2.33A or 20VDC/1.75A
It's unclear when or if Apple will release this dual power adapter but you can download the iClarified app or follow iClarified on Twitter, Facebook, YouTube, and RSS to be notified if it does!