One of the new features coming to Android 11 is "Bubbles." This feature allows you to multitask from anywhere on the phone. Similar to the Chat Heads feature found in the Facebook Messenger app, with "Bubbles" you can continue to engage in a chat while looking at another app without having to switch back and forth between the Messages app and, for argument's sake, a sports app.
For example, let's say that you are texting your girlfriend but at the same time you're following your favorite team on ESPN. Instead of having to move from app to app, a floating avatar will appear on ESPN. It shows the image of your girlfriend, the icon of the Messages app, and a preview of her message. The message turns into a blue dot on the "Bubble." Tap on it and it expands to give the user the full capabilities of the Messages app. That means that the user can access video, photos, emoji, Assistant suggestions, and other Messages feature.
According to 9to 5Google, version 11.21 of the Google app includes two new strings of code. One string name that cites a "Chat Head" tutorial goes on to say, "Tap to talk to your Assistant.\nDrag to move or dismiss." The second string of code says, "Assistant Chat Head dismissal area." 9to5Google enabled the Assistant Chat Head on the aforementioned version of the Google beta app. It is the current Assistant logo against a white background.
Now you might be curious as to why on earth would you need a Chat Head for Google Assistant. Messages, you can understand, but a digital assistant, well that's another story. But if you are using Google Assistant, the conversation that you're having is with the digital assistant and you might want to ask a follow-up question to a response you've received from it. Instead of switching from another app to do so, with Chat Heads, you can remain on the other app while Google Assistant's Chat Head responds to your inquiry.
Right now, tapping on the Assistant's Chat Head merely reveals the current Google Assistant panel at the bottom of the screen. When the final version of Android 11 drops, we'd expect to see the Chat Head expand as it does for Messages with a full-sized page sporting an optimized UI.