Google adds what's new and what's trending sections in the app directory within the Assistant experience that will constantly change and evolve over time. Autocomplete in the directory's search box is also available now.
In addition, new subcategories can be used in the App directory which improves the searchability of apps. If you now click on a category like “Food & Drink”, apps are broken down into additional subcategories, like “Order Food” or “View a Menu.” Google uses app descriptions and sample invocations to map users' natural search queries for those new task-based subcategories. As Google writes, the updated labelling taxonomy improves discovery for apps, as “will now surface for users in all relevant subcategories depending on its various capabilities.”
Developers can also customize their apps so that the user doesn't have to mention the app to invoke a specific task by precise action invocation phrases. Google calls that new feature Implicit discovery. Apps can register contextual queries (e.g., “book an appointment to fix my bike“) which makes the whole experience with Google Assistant much more fluid.
Lastly, with a new push notification API, apps can now Google Assistant to push asynchronous updates to users.