In reply to ABD_91:
“deterministic but arbitrary” means a tool can chose any ordering as long as it is consistent. If you iterate of the array multiple times, you always get the elements in the same order. That is also for random and debug stability; when you re-run a simulation, you always get the same ordering.
The ordering you are seeing is based on the creation order of the object. But creation order of the element would also be acceptable.
The LRM does not define (might to even allow) how a class handle should be display. That is a tool specific extension.