Index: en_US.ISO8859-1/books/porters-handbook/makefiles/chapter.xml
===================================================================
--- en_US.ISO8859-1/books/porters-handbook/makefiles/chapter.xml	(revision 54016)
+++ en_US.ISO8859-1/books/porters-handbook/makefiles/chapter.xml	(working copy)
@@ -2489,13 +2489,18 @@
 		<varname>GH_ACCOUNT</varname>,
 		<varname>GH_PROJECT</varname>,
 		<varname>GH_TAGNAME</varname>, and
-		<varname>GH_SUBDIR</varname> into a single variable.
+		<replaceable>group</replaceable><literal>/</literal><varname>GH_SUBDIR</varname>
+		into a single variable.
 		The format is
 		<replaceable>account</replaceable><literal>:</literal><replaceable>project</replaceable><literal>:</literal><replaceable>tagname</replaceable><literal>:</literal><replaceable>group</replaceable><literal>/</literal><replaceable>subdir</replaceable>.
 		The
 		<literal>/</literal><replaceable>subdir</replaceable>
 		part is optional.  It is helpful when there is more
-		than one GitHub project from which to fetch.</entry>
+		than one GitHub project from which to fetch.
+		Note that <replaceable>group</replaceable> and
+		<replaceable>/subdir</replaceable> are not separated
+		by a <literal>:</literal> like the other
+		parameters.</entry>
 	    </row>
 	  </tbody>
 	</tgroup>