tachiyomi/app/src/main/res/layout/source_main_controller.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/recycler"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        tools:listitem="@layout/source_main_controller_card" />

    <eu.davidea.fastscroller.FastScroller
        android:id="@+id/fast_scroller"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_gravity="end"
        app:fastScrollerBubbleEnabled="false"
        tools:visibility="visible" />

</FrameLayout>