ant/org.eclipse.ant.tests.ui/testbuildfiles/antextpoint.xml

<project default="ep-B">
    <target name="A" />
    <extension-point name="ep-B" depends="A" />
    <target name="B" extensionOf="ep-B" depends="D" />
    <target name="C" depends="ep-B" />
    <target name="D" />
</project>