Google introduced Chrome custom tabs five years ago, and most apps use them these days. Instead of creating their own custom browsers, developers can just hand over websites to a Chrome tab without the added bulk of a regular browser interface. The advantage is that devs don't have to spend resources on creating their own webview implementations and that users can quickly open these custom tabs in proper Chrome without reloading or losing their scroll position. It's a great system. But Google wouldn't be Google if it stuck with a great system (looking at you, YouTube Music).
A long time ago (prior to 2018, to be specific), Google Assistant's settings came without the now-familiar tabbed interface. Much like the system settings, different sections were accessible via top-level entries. It looks like Google is experimenting with a return to something akin to that old interface. A current A/B test spotted by 9to5Google puts a search bar at the top of the settings and gets rid of the tabs.
Facebook has been working on a bottom bar for its Android app for quite some time now. Last year, we saw a wild redesign that added a big "F" menu button in the middle, flanked by quick access to the news feed and notifications. That design appears to have been shoved back into the drawer, making way for a new experiment that looks much more conventional. The latest A/B test just takes the familiar top section bar and moves it to the bottom of the screen, which doesn't look too different from the iOS app.
Google Assistant isn't only good at answering your questions and orders. It also proactively sends you notifications on flights, public transport updates, packages, upcoming events, and more. To personalize which of these you receive, you usually have to head to the Google app's App info -> Notifications section. That's not very intuitive, and the amount of Assistant options there is limited. In a change that's already rolling out to first people, Google has moved the notification controls to a more prominent place right inside the Assistant's settings and has added many more granular toggles.
Over the last few years, the YouTube creator community has grown closer together and collaborations have become a regular occurrence. To make it easier for you to find out which YouTubers participate in a video, Google is A/B testing a new 'featured in this video' section on Android. In it, you'll find an overview of partaking creators complete with links to their channels and the option to subscribe.