A power plug is not included in the scope of delivery.
This decision was made mainly for ecological reasons, since most households now own such a power plug. You can charge the Healy with the USB cable in conjunction with any power plug with a USB port.
It does not matter what type of USB charger you use. Healy contains an internal control mechanism that regulates the current. All you need is a current of at least 100 mA, which any charger can provide nowadays.