OneDrive System Folder Integration - Technical Implementation Details

I'm seeking technical clarification on two related aspects of OneDrive's system folder integration:

1. Folder Redirection Implementation:

• In Windows 11, system folders are relocated from %userprofile%/{Documents,Desktop,etc} to %userprofile%/OneDrive/{Documents,Desktop,etc}
• Many legacy applications hardcode the traditional %userprofile% paths
• Question: What mechanism maintains compatibility for these applications? (Symlinks, junction points, shell redirects, etc?)
• Documentation gap: While this must be documented somewhere given enterprise deployment needs, we haven't located clear technical details

1. Shell Overlay Handler Behavior:

• OneDrive periodically resets its shell overlay icon priorities in HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\ShellIconOverlayIdentifiers
• This impacts organizations using multiple cloud storage providers
• Question: What triggers these registry resets? (Updates, scheduled tasks, specific events?)
• We observe changes every few days but can't identify the pattern

This information would be valuable for:

• Enterprise deployment planning
• Custom folder redirection implementation
• Multi-cloud storage integration
• Maintaining reliable sync status indicators