Gadgetbridge/app/src/main/res/xml/devicesettings_sleep_mode_schedule.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.preference.PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
    <PreferenceScreen
        android:icon="@drawable/ic_activity_sleep"
        android:key="prefs_sleep_mode_schedule"
        android:persistent="false"
        android:title="@string/pref_sleep_mode_title">

        <SwitchPreferenceCompat
            android:defaultValue="false"
            android:icon="@drawable/ic_activity_sleep"
            android:key="sleep_mode_schedule_enabled"
            android:summary="@string/pref_sleep_mode_schedule_summary"
            android:title="@string/pref_sleep_mode_schedule_title" />

        <nodomain.freeyourgadget.gadgetbridge.util.XTimePreference
            android:defaultValue="22:00"
            android:key="sleep_mode_schedule_start"
            android:title="@string/bedtime" />

        <nodomain.freeyourgadget.gadgetbridge.util.XTimePreference
            android:defaultValue="06:00"
            android:key="sleep_mode_schedule_end"
            android:title="@string/wake_up_time" />
    </PreferenceScreen>
</androidx.preference.PreferenceScreen>