session-android/res/menu/settings_general.xml

<?xml version="1.0" encoding="utf-8"?>
<menu
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">

    <item
        android:id="@+id/action_change_theme"
        android:title=""
        android:icon="@drawable/ic_ui_mode_24"
        app:showAsAction="always" />

    <item
        android:id="@+id/action_qr_code"
        android:title=""
        android:icon="@drawable/ic_qr_code_24"
        app:showAsAction="always" />

</menu>