It looks like the regulator is a Torex XC9258, 1A at 3.3V. That includes powering the device itself, so not all of that is available to the FeatherWings. However, especially for the Xenon, the device itself doesn’t require much power.
Also, of course if you are powering by a 500 mA computer USB port, you won’t get the full 1A either.