-If 'coord_auto' is null, and latitude and longitude are not null, then
-latitude and longitude are also essential fields.
-
-All other fields are considered "non-essential". If a non-essential field is
-empty in this location, it will be ignored in determining whether an existing
-location matches.
-
-If a non-essential field is non-empty in this location, existing locations
-that contain a different non-empty value for that field will not match. An
-existing location in which the field is I<empty> will match, but will be
-updated in-place with the value of that field.
+All other fields are considered "non-essential" and will be ignored in
+finding a matching location. If the existing location doesn't match
+in these fields, it will be updated in-place to match.