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

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

    <LinearLayout
        android:id="@+id/catalogue_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical"
        tools:context=".ui.browse.source.browse.BrowseSourceController">

        <FrameLayout
            android:id="@+id/progress"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:visibility="gone"
            tools:visibility="visible">

            <com.google.android.material.progressindicator.CircularProgressIndicator
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_gravity="center"
                android:indeterminate="true" />

        </FrameLayout>

    </LinearLayout>

    <eu.kanade.tachiyomi.widget.EmptyView
        android:id="@+id/empty_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="center"
        android:visibility="gone" />

</FrameLayout>