If tags in local files have a different value then on the MusicBrainz server (or even if you changed the original value), you could use the command "Use Original Value" (Germand: "Ursprünglichen Wert benutzen") from the context menu.
In this case the "New Value" will be set to the "Original Value".

In 2.4 and 2.4.1 this is not working like expected: It looks like the "New Value" will not be changed. The change is done, but there is no refresh.