Ah, OK.

You know that they have existing PaaS (windows only "cloud apps" that run your code in a scalable way without you having to worry about managing the Windows OS it is running on) and IaaS (Windows/Linux VMs where you provision the OS, and manage it yourself).

This is kind of the next generation of that where you get your code run in a managed environment (so kind of like PaaS) but you get to choose the platform (kind of like IaaS) - and it has the same model for running your code on prem, in the cloud, or a mix of the two.

With a whole bunch of other services to help you do that more efficiently/scalably/reliably.

At least, that's what the diagrams and commentary seem to imply!