Assuming my calculation is accurate, 90,000,000 hours of video using around 30 PB comes to an average bit rate of about 760k. (Hard to guess though bc I doubt they’re using up all the space they provision day1)

So my guess is either CCTV type of footage where there’s large gaps of motion / high GOP / big codec gains - or something like desktop recordings which are generally very low bit rate even though they can be high res. At that bitrate I can’t imagine it’s something like YouTube video. (Unrelated to the bitrate maybe it’s something like all older public domain videos). I would love to have an idea of what type of videos they are using (just out of curiosity)