I ask as a dilettante, so please feel free to correct or emend this.
I transcribe the radio altimeter enunciations for https://www.youtube.com/watch?v=Vr-0LiQA6wo:
0m 21s: 400
0m 23s: 400
0m 36s: 100 above
0m 41s: 200
0m 49s: 100
Are the radio altimeter verbalisations part of the Ground Proximity Warning System?
Why was 400 uttered twice? Isn't the A380 descending?
Same question for 100 at 49 s, compared with 36 s?
What does the above imply?