packages/SystemUI/res/layout/qs_carrier.xml

<!--
  ~ Copyright (C) 2019 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
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<com.android.systemui.qs.carrier.QSCarrier
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/linear_carrier"
    android:layout_width="wrap_content"
    android:layout_height="match_parent"
    android:minWidth="48dp"
    android:orientation="horizontal"
    android:gravity="center_vertical|start"
    android:background="@android:color/transparent"
    android:clickable="false"
    android:clipChildren="false"
    android:clipToPadding="false"
    android:focusable="true" >

    <include
        layout="@layout/mobile_signal_group"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginEnd="@dimen/qs_carrier_margin_width"
        android:visibility="gone" />

    <com.android.systemui.util.AutoMarqueeTextView
        android:id="@+id/qs_carrier_text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:textAppearance="@style/TextAppearance.QS.Status"
        android:textDirection="locale"
        android:marqueeRepeatLimit="marquee_forever"
        android:singleLine="true"
        android:maxEms="7"/>

</com.android.systemui.qs.carrier.QSCarrier>