Hello,

I am not sure that alnnost "mechanically" changing every occurrence of amenity=square into place=square is useful.

Yes, amenity=square is definitely a tag error and should not exist.  But if you take this example, way 1247481865 which you retagged already has "highway=pedestrian", "area=yes" and a name, so the additional tag does not bring any benefit.  Even worse: had you inspected the object correctly, you would have found out it is inside a multipolygon with place=square.

So, now, after your changeset we have a really strange situation with nested place=square areas.  IMHO it should be corrected: tag place=square on the outer area only, remove the tag from the pedestrian area and remove the multipolygon itself, which was not correct.