They basically threw a gigantic net out (I was contacted by multiple recruiters about it and saw their ad in increasingly more places as time went on) and then (I heard) hired internally somehow and simply stopped considering other applicants. Regardless, I never heard any feedback which leads me to suspect they found somebody good enough and then decided they didn't want to deal with the recruiting Crusade they kicked off for the position. Given that their process actually involves a take-home challenge/test, I suspect they wasted a lot of people's time.
I'm not outraged or anything but I do think that if you're going to have a more involved interview process than is typical, you need to think about the fact that people are prioritizing your opportunity over finding leads or prepping for other hiring processes that might be more involved than is typical.