The adaptive shell for Windows 10 that Microsoft is presumably working on is still very far off, but that hasn't stopped some from creating concepts of how it could work across devices.
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Microsoft's mobile commitments: "We expect to keep [flighting Mobile builds] beyond release of the Creators Update." "The future of Windows 10 Mobile is that we're continuing to invest in Mobile."
Microsoft currently maintains various UX shells for each type of device on which Windows 10 runs - but it's said to be developing a unified 'Composable Shell' that adapts the OS for all devices.