Yes, you can check the details about migrated Files/Attachments after migration. Follow the steps:
- Navigate to the "Mass File Migrate" app.
- Go to the "Migrated Files" tab. Here, for every migration, a new record will be created.
- You can check all details about the migration on the record details page.
PS: View Mass File Migrate Salesforce file migration app on Salesforce AppExchange:
https://appexchange.salesforce.com/appxListingDetail?listingId=e9874a66-2001-4e3d-8a29-3a2ed7f584c4