how to get rid of "title" attributes on "div" tags in html output

hi,

people complain about the title attributes on div tags, as those show up
as tooltips in browsers, just where you are reading.

e.g.

<book>
  <bookinfo>
    <title>tester Reference Manual</title>
    ...

becomes:

<div class="book" title="tester Reference Manual">

I can't find anything on
http://docbook.sourceforge.net/release/xsl/current/doc/html/index.html
to disable that. I am now digging the stylesheets for a while and I
found only this template
<xsl:template match="*" mode="html.title.attribute">
but that is just creating the titles for e.g. links. Any tips?

Stefan