packages/CarSystemUI/res-keyguard/layout/keyguard_num_pad_key.xml

<?xml version="1.0" encoding="utf-8"?><!--
  ~ Copyright (C) 2018 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
  -->

<!-- Car customizations
     The mnemonics is not shown for car but KeyguardPinView references the resource id in code.
     Removing it will cause the keyguard to crash. Hide them instead
-->
<merge xmlns:android="http://schemas.android.com/apk/res/android">
    <TextView
        android:id="@+id/digit_text"
        style="@style/Widget.TextView.NumPadKey"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        />
    <!-- The mnemonics is not shown for car but KeyguardPinView references the resource id in code.
         Removing it will cause the keyguard to crash. Hide them instead -->
    <TextView
        android:id="@+id/klondike_text"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:visibility="gone"
        />
</merge>