Because your backed-up data with Redstor is encrypted at all times, it is not possible to use ESE or the Storage Platform Console to query if a specific file can be restored, or to generate a report of all restorable files under a specific path.
If you need to determine if a specific file is contained in your ESE backed-up data, you can instead use a command such as
Get-ChildItem in PowerShell to query a drive that was mounted using InstantData Temporary.
Get-ChildItem -Path 'C:\ProgramData\Redstor Pro\Backup Client ESE' -Recurse –Force -ErrorAction SilentlyContinue -Include *.log, *back*set* | Out-File "C:\Users\$env:username\Desktop\PowerShellExport.txt"
This will create a file on the desktop called PowerShellExport.txt, which will contain all files whose file names meet the specified criteria (in this case the file names *.log and *back*set*).
Read more about PowerShell's Get-ChildItem cmdlet in this article from Microsoft's knowledge base.
Note: This method is only applicable to data that was backed up using an ESE agent.