fenix/app/src/main/res/layout/custom_search_engine_radio_button.xml

<?xml version="1.0" encoding="utf-8"?>
<!-- This Source Code Form is subject to the terms of the Mozilla Public
   - License, v. 2.0. If a copy of the MPL was not distributed with this
   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->

<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_height="@dimen/search_engine_radio_button_height"
    android:minHeight="@dimen/radio_button_preference_height"
    android:layout_width="match_parent"
    android:background="?android:selectableItemBackground"
    android:clickable="true"
    android:focusable="true">
    <RadioButton
        android:id="@+id/radio_button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:importantForAccessibility="no"
        android:textAlignment="textStart"
        android:textAppearance="?android:attr/textAppearanceListItem"
        android:layout_marginStart="@dimen/search_bar_search_engine_icon_padding"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"/>
    <TextView
        android:id="@+id/engine_text"
        android:textColor="?primaryText"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="@dimen/search_bar_search_icon_margin"
        android:layout_marginEnd="@dimen/radio_button_padding_horizontal"
        android:text="@string/search_add_custom_engine_label_other"
        android:textSize="16sp"
        app:layout_constraintStart_toEndOf="@id/radio_button"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>