<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE window SYSTEM "ftlk.dtd">

<window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
    <box align="center">
        <button label="&label1.title;"/>
    </box>
</window>

<?xml version="1.0" encoding="UTF-8"?>
<!ENTITY label1.title "For The Lich King">

XML Parsing Error: undefined entity
Location: file:///***/ftlk.utf-8.xul
Line Number 6, Column 9:
        <button label="&label1.title;"/>
--------^