Kudos to Catalans! Admirable success!
When I examined the data with the new delta page, I could see how it happened in time: Between v8.0 and v9.0 they had a huge campaign and recorded 320h/mo with ~6000 new users/mo. Although from there on a medium sized CV-dataset-sized data is added, the main emphasis shifted to validation of those ~1000h campaign recordings.
Recordings not-yet-validated are still a problem in global CV. One third of the recordings of 11k-hours worth are just waiting there…