It's basically the same one as the iPad Pro.
It's a pity Apple doesn't use components like Anker did for their 30W USB-C charger, that one is almost as small as Apple's 5W USB-A charger.
until I see the insides of that anker charger, I’ll trust Apple. The reason I say this is Apple has always built their chargers to be completely safe and efficient while also supporting great components. Over the years each of their chargers gets a tear down and every electrical engineer is always surprised how much work goes into each charger and how cramped it is but still well designed. on top of this, anytime a third party charger is taken apart especially a cheaper alternative that people love to rave about, they are a ****ing joke and safety hazard.
this isn’t me saying I don’t trust anker. I actually love their products and own cables, battery packed and two of their larger, MacBook sized chargers (one usb a and one usb c) chargers but the atom still makes me go 🤔. If they truly were able to shove 30 watts of power safely into the size of a iPhone 5w adapter while keeping it safe and well engineered then bravo and Apple needs to tell us why they couldn’t.
This article is a great example of Apple chargers versus third party / cheaper chargers.http://www.righto.com/2015/11/macbook-charger-teardown-surprising.html?m=1
There are many more but I have this bookmarked because it’s so well written and I use it the most when discussing this subject.
i did a quick search and it looks like anker shared on their own website

O) how they achieved the small design which is awesome!
https://www.anker.com/deals/powerport_atom
it looks like they are using GaN which is new tech that helps reduce the complexity of chargers. From a quick glance of this
https://www.mouser.com/applications/advancing-power-GaN/ it’s definitely promising but I can see why Apple isn’t read to just adopt something so new especially when it comes to power. I only skimmed it and will ask my electrical engineer buddies what they think about this but as a techie I can see why Apple hasn’t jumped on the bandwagon and made all their chargers with GaN. I’m sure they are testing it internally but they have to go with some they know that works and will be provided to millions of people that they will use for years versus something you buy on your own at your own risk and if something happens that’s between you and the company who made it.
definitely ordering a powerport atom pd 1 and using it for traveling and whenever I can to see how it does overtime, Heat generated by the adapter, how it handles power from multiple outlets, how it handles surges or the “cleanness” (my word) of power based on a raw outlet vs surge protector, etc.
thanks for sharing the anker adapter. Totally didn’t realize they had something so powerful at such a small package :O