It's not clear if the accessory firmware update was found in the iOS 9.3 software or whether iOS pinged a server to download the update before applying it.

Firmware updates of accessories usually need you to connect them to a Mac, but as the Smart Connector is unique to the iPad Pro, it’s likely this fact that prompted the new capability … ...

The second beta of iOS 9.3, which was seeded to developers on Monday and the public earlier today, includes a new feature that allows the iPad Pro's Smart Connector to update accessory firmware ...

Well, here's an interesting development. Some iPad Pro users have noticed that, with the latest version of iOS 9, their monstrous tablet is able to push firmware updates to a connected accessory ...

The second beta of iOS 9.3 allows iPad Pro owners to update the firmware on some accessories by way of the Smart Connector, AppleInsider can confirm.