Android 12's Conversation widget is starting to appear for more folks again, following an early appearance in Android 12 DP3. It still isn't live for everyone, but it's started showing up on us for a Pixel 4 XL running Beta 2 without any digging around in activities or root to surface hidden features.
The new Conversation widget appeared for us as an option in the widgets menu, aptly under "Conversations," though back in Dev Preview 3, it was under System UI. We don't know how much functionality may have changed since then since it wasn't live for us at the time, but we can document how it works now as of Beta 2.
