Computer Configuration > Administrative Templates > Microsoft Edge > Content settings
Both
HKLM\Software\Policies\Microsoft\Edge
If you set this policy to 3, websites can ask for write access to the host operating system's filesystem using the File System API. If you set this policy to 2, access is denied. If you don't set this policy, websites can ask for access. Users can change this setting. Policy options mapping: * BlockFileSystemWrite (2) = Don't allow any site to request write access to files and directories * AskFileSystemWrite (3) = Allow sites to ask the user to grant write access to files and directories Use the preceding information when configuring this policy.