I would say "Protected against solid objects over 1mm, e.g. wires & nails." and "Protected against direct sprays of water up to 15 degrees from the vertical." so IP42, but depends could be IP44. But why do you want to know? And it is easy enough to google IP ratings.
I understand it's unlikely to get 'too wet', but looking at it, it appears to be a standard open-backed batten holder, so only really suitable for indoor use I'd have thought.
As for impact, I've been told the bulb has been smashed at least once (It's in a small 'Village Town' in the 'Sticks' of Wales, but one with a strong reputation for P1ssheads and the like).
It does depend on location the light shown is well protected, and the door rarely used, one needs to walk around the house past the kitchen door to reach it, I have never had a visitor go to that door, and unlikely we will use it as patio doors into dinning room next to it.
The old 13th edition referred to "mounted at such a height that they cannot readily be touched" and one is not permitted to set a trap, but one can watch some one blunder into one, or you could when I was at collage. So if it does not cause the owner a problem then why change it?
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