While making a few minor improvements, I discovered that a number of nodes of a certain way has been shifted, causing 'spaghetti'. One of them is
I managed to get it more or less back into the same place.
A search with JOSM (string 'user:Justy') revealed this user also reversed the direction of a oneway :
I guess at some point I must grep the whole planet for this user name and then go through the tedious task to see if he made more mistakes. (I don't feel like messaging him...)
Getting proper history functionality will be difficult to implement. See