packages/CarSystemUI/res/layout/sysui_overlay_window.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
  ~ Copyright (C) 2020 The Android Open Source Project
  ~
  ~ Licensed under the Apache License, Version 2.0 (the "License");
  ~ you may not use this file except in compliance with the License.
  ~ You may obtain a copy of the License at
  ~
  ~      http://www.apache.org/licenses/LICENSE-2.0
  ~
  ~ Unless required by applicable law or agreed to in writing, software
  ~ distributed under the License is distributed on an "AS IS" BASIS,
  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  ~ See the License for the specific language governing permissions and
  ~ limitations under the License.
  -->

<!-- Fullscreen views in sysui should be listed here in increasing Z order. -->
<FrameLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:background="@android:color/transparent"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <!-- TODO(b/151617493): replace marginBottom with insets. -->
    <ViewStub android:id="@+id/notification_panel_stub"
              android:layout_width="match_parent"
              android:layout_height="match_parent"
              android:layout="@layout/notification_panel_container"
              android:layout_marginBottom="@dimen/navigation_bar_height"/>

    <ViewStub android:id="@+id/keyguard_stub"
              android:layout_width="match_parent"
              android:layout_height="match_parent"
              android:layout="@layout/keyguard_container" />

    <ViewStub android:id="@+id/fullscreen_user_switcher_stub"
              android:layout_width="match_parent"
              android:layout_height="match_parent"
              android:layout="@layout/car_fullscreen_user_switcher"/>

    <ViewStub android:id="@+id/user_switching_dialog_stub"
              android:layout_width="match_parent"
              android:layout_height="match_parent"
              android:layout="@layout/car_user_switching_dialog"/>

</FrameLayout>