So that last-second leak wasn't coming out of nowhere, and Apple has just announced the iPad is getting its own operating system. iPadOS, which is a really stupid name - even if it is perfectly literal.
It's an optimised piece of software for Apple's tablet devices, and that means its coming with new features like pinning widgets to the home screen (Android in 2010 called and would like its features back). It'll also come with much more powerful multitasking, including the option to open multiple windows of a single app. That works for third party apps too, not just ones made by Apple.
Think of the whole thing as a mix of iOS and MacOS, turning the iPad into a device more akin to the laptop - which really has been Apple's plan all along. So you also get desktop-like features, including fonts, desktop web browsing, a download manager, and better folder support.
Obviously everything will be optimised for a touch-display, so it's not clear whether iPadOS will offer external mouse support. Knowing Apple it would all be touch-based, which would explain why it spent so much time explaining various new touch-gestures, but we don't have proper confirmation of that right now.
Oh and there's official support for external USB drives, and about fucking time too. We'll bring you more about iPadOS as we learn it.