This has been posted about in the Update and Domain/North Austin threads, but it's big enough to be in a dedicated thread.
It has a name now, and ground breaking is expected in early 2019. There will be ~300K sq. ft. of office space and close to 300 apartments.
The Statesman article linked to below the rendering doesn't include the parking levels in the floor count. Also, the exact floor count doesn't seem to be nailed down based on public info.
It's designed by Page, and the potential MLS stadium seems to be a catalyst.
Statesman:
https://www.mystatesman.com/business...jdPn5NEOLISCN/