Yate does its best to keep track of files that are loaded. Whenever you attempt to Save files, the file location is validated and updated if necessary. Further, if the files have been externally modified, Yate will inform you about the fact.
If you are working in Yate and you use another application to modify the loaded files, you might want to tell Yate to update the loaded information immediately. If a file has not been modified, this simply requires the reloading of the file. If a file has been modified, you might be okay with discarding the changes and reloading, or not, which would give you time to export the metadata.
The Refresh command tests all loaded files to see if they were externally modified. If they were, you will given the option to reload the files. You can optionally set that all modified files be reloaded if no changes have been made.
This is a convenience function that need only be used in you are possibly modifying the same files in Yate and at least one other application at the same time.