ProBundle versions of HubConnect v2.0 from behind the "free wall" have been released. The difference is that ProBundles don't expose the code — if you need to explore it, it's all available at HubConnect.to.
In most cases, using HPM (Hubitat Package Manager) to add these Bundles to your hub will be simpler. Follow the same logic as below regarding which 2 of 3 bundles HPM installs.
You've never run HubConnect before. Install both of these on your Hubitat hub.
You already have Server + Drivers running on hub #1. On the second hub, install these instead.
Home Assistant takes the place of a second Hubitat hub, so you won't need the Remote bundle at all — just Server + Drivers here, then head to the HA setup guide.
Need the raw bundle URLs on their own? They're the same three files — Server, Remote, and Universal Drivers — just grouped above by which two you'll actually use.
Select Bundles from the main menu and click Import Zip in the upper right.
Hubitat — Bundles screen
Select the Download from a URL tab, check This is a private pro installer bundle, then paste in either the Server bundle URL or the Remote bundle URL above. Click Import.
Hubitat — Bundles import screen
Hubitat — Bundles result screen
UniversalDriver URL, or use Hubitat Package Manager for the Universal Drivers instead.