We removed hitgroups in favour of Hitbox Tags, similar to how we use them for collisions. Here's how they work.
When editing a hitbox from ModelDoc, you'll see Hitbox Tags. Populate them with some useful keywords like so:
When running traces, you'll see TraceResult.Hitbox. That'll hold all the info you'll need when interacting with hitboxes. We also pass it with DamageInfo.
Before, you'd be given a hitbox index, and that's it. It wasn't elegant at all.
With hitbox tags, it's way more explicit:
You can also grab the hitbox's name with Hitbox.GetName() - useful for debugging.