The model utilities in Anvil are an extended set of tools like those found in the Utilities rollout of Wall Worm Model Tools. These tools are primarily for manipulating the settings and properties of groups of WWMT models in the scene as well as their proxies.
Wall Worm Proxy Tools
This rollout lets you create proxies, set prop types, collect skins from proxies and include/exclude models/proxies from exporting in the VMF. Read more on proxies...
WWMT Model Functions
By and large, these functions work on selected WWMT helpers. Some are already detailed here: WWMT Utilities Rollout.