OneDrive Placeholders used to be an interesting feature that would allow you to save on storage space on your PC and also have a “Placeholder icon” for a file in OneDrive cloud on your PC. So, what it actually meant is while you have an icon showing a file on your system, it wasn’t stored locally. Only when you double-click on this file icon it will get downloaded to your PC from cloud. This feature was removed by Microsoft as it was bit confusing for common users but there were many who were unhappy with it gone.
Now, a new rumor claims that this features may be back with Windows 10 Redstone update. So, add it to the list of expected / rumored features of Windows 10 Redstone. Microsoft just pushed first Redstone build, Build 10082 to Insiders but it came without any new features. But next Redstone builds may bring the new features and we can expect the Placeholder to be one of them hopefully soon.
You can read all about Redstone by clicking here.