New Android 15 Project Mainline monthly updated module: WebViewBootstrap
https://www.androidpolice.com/android-15-webview-bootstrap-module/

Google is working on a new Project Mainline module in Android 15 called
WebViewBootstrap. Project Mainline is an initiative Google introduced with
Android 10 that modularizes OS components so feature and security updates
can be delivered through Google Play instead of through regular OTA
updates. If you've ever seen a Google Play System Update pending on your
Android device, that's how Project Mainline modules are updated.

Although the public code repository for WebViewBootstrap is currently
empty, we have an idea of what Google plans to do with this new module
thanks to two sources. According to our sources, Google plans to move a
bunch of code related to Android's WebView API to this new WebViewBootstrap
module. This includes code under the following directories:

frameworks/base/core/java/android/webkit
frameworks/base/services/core/java/com/android/server/webkit
frameworks/base/native/webview
Google wants to move this code to the new WebViewBootstrap module so that
it can update the code in emergency situations, such as when WebView is
unable to start. Our sources tell us that Google only intends to push bug
fixes through updates to the WebViewBootstrap module, so there won't be any
new functionality or API changes that developers will have to worry about.
Supposedly, this module will also have some new "resilience" features that
aim to automatically detect and repair when WebView is unable to start.

Apparently, the plan is for this new module to launch with Android 15.

However, it may be optional for OEMs to include in their own builds, at
least with the coming release. Instead, Google seemingly plans to make it
mandatory in the following release, i.e., Android 16. The WebViewBootstrap
module hasn't appeared in the public Developer Preview 1 release of Android
15, but we'll keep an eye out to see if it lands in Developer Preview 2.

Andrew wrote on Tue, 18 Jun 2024 21:50:46 -0000 (UTC) :

> Apparently, the plan is for this new module to launch with Android 15.

I'm not sure if this older information ever made it into Android 15...
<https://www.androidpolice.com/project-mainline-android-14/>

Project Mainline in Android 15: What to expect
Finally, here's a sneak peek at some of the new APEX/Project Mainline
modules we may see in next year's Android 15 "Vanilla Ice Cream" release:

CrashRecovery:
I have no idea what this will do. There's an empty repository in AOSP for
it, but that's all that's public so far.
NFC: As I previously reported, Google is working on turning Android's NFC
stack into a modular system component. There's no code for this in AOSP
repositories yet, but a commit description from a Googler suggests it'll
happen.

RemoteAuth(entication):
It's not entirely clear what RemoteAuth is for, but based on my initial
reading of the code that's public, it seems like it'll let you use a
UWB-enabled smartwatch as a "remote authenticator." Perhaps this will let
you use your smartwatch to unlock apps on your phone in the future.

ThreadNetwork (part of Connectivity):
Google is actively working on a Thread network stack for Android that's
decoupled from Google Play Services. Thread, if you aren't aware, is a
wireless protocol designed for Matter-enabled devices.

UWB vendor HAL will become updatable:
Android 13 introduced an (optional) UWB Mainline module, though only the
system-side HAL was updatable. In Android 15, however, the vendor-side HAL
will become updatable.

That's my high-level summary of what to expect in Android 15.