packages/SystemUI/res/drawable/qs_tile_background.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
  ~ Copyright (C) 2021 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.
  -->
<ripple xmlns:android="http://schemas.android.com/apk/res/android"
    android:color="@color/qs_tile_ripple_color">
    <item android:id="@android:id/mask"
        android:drawable="@drawable/qs_tile_background_shape"
        />
    <item android:id="@id/background">
        <layer-list>
            <item
                android:id="@+id/qs_tile_background_base"
                android:drawable="@drawable/qs_tile_background_shape" />
            <item android:id="@+id/qs_tile_background_overlay">
                <selector>
                    <item
                        android:state_hovered="true"
                        android:drawable="@drawable/qs_tile_background_shape" />
                    <item
                        android:state_focused="true"
                        android:drawable="@drawable/qs_tile_background_shape" />
                </selector>
            </item>
        </layer-list>
    </item>
</ripple>