2.1/user/src/com/google/gwt/place/Place.gwt.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE module PUBLIC "-//Google Inc.//DTD Google Web Toolkit 0.0.999//EN" "http://google-web-toolkit.googlecode.com/svn/tags/0.0.999/distro-source/core/src/gwt-module.dtd">
<module>
  <inherits name='com.google.gwt.user.User'/>

  <source path="shared"/>
  <source path="impl"/>
  <generate-with class="com.google.gwt.place.rebind.PlaceHistoryMapperGenerator">
    <when-type-assignable class="com.google.gwt.place.shared.PlaceHistoryMapper"/>
  </generate-with>
</module>