The help data XML file is used by products to control the order of books
      in the help table of contents, as well whether or not books or keyword
      index sets should be displayed at all. The file must be referenced in the
      product's plugin_customization.ini file using the
      org.eclipse.help/HELP_DATA property.
    
<!ELEMENT extensions (tocOrder? , hidden?)>
The extension data for Help.
<!ELEMENT tocOrder (toc | category)*>
Specifies the order in which top-level table of contents entries (also called "books") or categories of books should appear in Help. If one of the items listed is not available, it is ignored. If there are items available that are not listed and not hidden, they will be displayed after the ones listed here.
<!ELEMENT toc EMPTY>
<!ATTLIST toc
id CDATA #REQUIRED>
A reference to a top-level table of contents (TOC) entry, also called a "book".
/<plugin_id>/<path>/<file>" (e.g.,
        "/org.eclipse.platform.doc.user/toc.xml"). In general,
        this is the ID of the TocContribution supplied by its
        originating AbstractTocProvider.
      <!ELEMENT category EMPTY>
<!ATTLIST category
id CDATA #REQUIRED>
      A reference to a category of top-level table of contents (TOC) entries
      (books). Categories are implicitly created when a table of contents
      contribution declares itself to be of that category, for example, by
      specifying a category attribute for the toc
      element in the org.eclipse.help.toc extension point.
    
<!ELEMENT (toc | category | index)*>
Contains a set of help items that should be hidden from the user.
<!ELEMENT index EMPTY>
<!ATTLIST index
id CDATA #REQUIRED>
A reference to a contribution of help index keywords.
/<plugin_id>/<path>/<file>" (e.g.,
        "/org.eclipse.platform.doc.user/index.xml"). In general,
        this is the ID of the IndexContribution supplied by its
        originating AbstractIndexProvider.
      The following example shows how to arrange the following books in the order shown:
user.intro")
      in /com.xyz.doc.user/introToc.xml
      user.content") in
      /com.xyz.doc.user/usingToc.xml
      user.reference")
      in /com.xyz.doc.user/refToc.xml
      As well as hide the following books/categories and related keyword indexes:
none) in
      /org.abc.doc.isv/toc.xml
      isv.reference") in
      /com.def.doc.isv/toc.xml
      isv.reference") in
      /com.ghi.doc.isv/toc.xml
      The markup would be the following:
<extensions> <tocOrder> <toc id="/com.xyz.doc.user/introToc.xml"/> <category id="user.content"/> <toc id="/com.xyz.doc.user/refToc.xml"/> </tocOrder> <hidden> <toc id="/org.abc.doc.isv/toc.xml"/> <category id="isv.reference"/> <index id="/org.abc.doc.isv/index.xml"/> <index id="/com.def.doc.isv/index.xml"/> </hidden> </extensions>
org.eclipse.help, including the default help implementation
    provided by Eclipse.
    
      Copyright (c) 2006, 2011 IBM Corporation and others.
      All rights reserved. This program and the accompanying materials are made
      available under the terms of the Eclipse Public License v1.0 which
      accompanies this distribution, and is available at http://www.eclipse.org/legal/epl-v10.html