iCloud on MacBook downloading stuck. How to identify what files are downloading?

Make sure iCloud Drive and desktops and documents box is turned on in Mac system preferences Add your Desktop and Documents files to iCloud Drive - Apple Support

Use iCloud Drive to store documents on your Mac and iOS devices - Apple Support 

Read the articles Access and manage your files in iCloud Drive - Apple Support

Get file, folder and disk information on Mac – Apple Support

• Pie chart: The pie chart status icon gradually increases from clear to dark as the files are transferred.
• The same pie chart can also appear next to iCloud Drive in the sidebar, where it indicates the overall progress for files transferring to and from iCloud Drive.
• The read and write permissions must be correct Change permissions for files, folders or disks on Mac - Apple Support 
• Download items from the web using Safari on Mac - Apple Support 
• If you need permission to open an item on Mac - Apple Support

There is no way to find which file / or folder is downloaded from iCloud.com , the complete iCloud data syncs .

Hey JBTanSG,

Thank you for using the Apple Support Communities! We understand there is a pop up regarding items downloading and it appears to be stuck. Let's see how we can help.

You looked over a good article, 'Access and manage your files in iCloud Drive'. Do you suspect the files are related to ones in iCloud? What were you doing on your Mac prior to this pop up appearing?

If you restart your Mac, does it warn you about anything related to the affect it might have on the items downloading? If not, we suggest restarting to see if that helps with this.

Best regards.