The latest version of the official Google app had a recent APK teardown by 9to5Google, and it shows that direct control of Google Podcast functionality will be returning to Android Auto, among other finds. Perhaps the biggest change aside from Android Auto getting its podcasts back is the arrival of categories for actions in Google Assistant. There are now various categories in both the suggested actions, and in the Explore tab containing third-party actions that you can equip Assistant with.
Going into the settings for Assistant, you'll find that the top section is now significantly smaller. The user portrait and name have been shrunk down to a small bar up top, about the size of one of the settings category headings. This makes it a bit easier to navigate the settings menu, since you'll no longer have to scroll down to access the full list of settings categories.
Finally, Collections is going to be getting a new capability some time soon. When you add things to your Collections pages, you'll start seeing recommendations for similar content. Pages, images, and other content are all on the menu, according to the feature's text within the APK. It's not out just yet, but with some refinements over the base system laid out in the last update, it seems to be nearing completion.
It is worth noting that 9.31 is currently the beta version, and not available in the normal channel just yet. To get it, you'll have to sign up as a beta tester for the app in the Play Store. To do that, you can head to the bottom of the Google App's listing in the Play Store, where you'll find a prompt that allows you to sign up for the beta. From there, just confirm your sign-up, then you can update the app to the latest beta version. Naturally, you can drop back to the stable app at any time.
Most of these changes build on and tweak a few things that have happened to the app recently. Google Podcast support in Android Auto, for example, was originally added as recently as this January. A more recent update removed the functionality, and now it's on its way back. The changes to Collections, as mentioned above, are adding onto earlier changes and building toward a grand feature rollout.
All of the changes in this update have an overarching theme. They're indicative of Google trying to figure out what works best as far as user interface and ease of use. The back and forth nature of the Google Podcasts feature in Android Auto is the clearest case of that, but the tweaking of how the settings menu for Assistant looks is arguably a change that's easy enough to roll back if need be.
The upcoming change to Collections, meanwhile, makes the app easier to use by playing to two of Google's biggest strengths; collecting and extrapolating user data, and using AI to make actionable decisions, plans, and guesses based on that data. Since the two smaller features are live in the beta, those who don't sign up will probably see them soon. Since they are in beta, of course, it's possible that Google may do away with them before they reach the stable app.