See http://musicbrainz.org/edit/22405093 for instance.

What does that summary tell me?

1.) The changes must have been absolutely fundamental and plenty for I have to scroll down twice the height of my monitor, past screaming colours, to get to the edit note.
2.) He apparently re-wrote the complete tracklist, he might even have changed the position of each and every track. For some reason the #s are still the same, though, but in different lines. Did he accidentally create a non-sequential tracklist? Hm.
4.) Before 2013-06-06, this release's tracks were not linked to any recordings – at least that's what the lower part tells me. The upper part says he didn't change recordings at all b/c the recordings IDs are identical. But I have to hover over them to check.
5.) What on earth are track MBIDs as mentioned in the icon tooltip? They don't show up in the editing process, why mention them in the summary?

These statements are not rhetorical, I simply don't know what the summary is trying to indicate. Now imagine someone reviewing these edits who hasn't spent several years on the website.