Most of it is new really. Taking into account the above feedback, the main changes are as follows
- barrier=kerb and kerb= on nodes or ways can be used together, it’s not one or the other; kerb as a subkey of barrier=kerb
- kerb= when used by itself at the actual location of the kerb should also get barrier=kerb, for clarity
- clarification on how to tag exact height
- if you see barrier=kerb on a road where there isn’t actually a kerb that cars have to go over, that’s a mistake and should be corrected
- usage of kerb=* (or only kerb=raised?) to mean that there is a kerb on each side of the way at this point; especially (or only?) in places where one might expect a crossing, because a footway meets a road: this usage is discouraged because of the ambiguity; do not add barrier=kerb here
If no one objects I’ll add Martin’s suggestions too
- for crossings, either map the kerb separately (barrier=kerb plus optionally kerb=) or put kerb= on the crossing node; but not both
- for separately mapped barrier ways, it is still advisable to put barrier=kerb on the intersection with the highway