With the release of Windows 10 Insider build 17650, Microsoft added a new stripped down version called "Windows Lean" that uses approximately 2GB less space… | Cose
Windows 10 'Lean' is a smaller edition of Windows 10 for devices with 16GB of storage | Windows Central
Microsoft working on Windows 10 Lean edition for devices with less storage - The Verge
Windows 10 Lean - невышедшая редакция Windows 10 - YouTube