The html strings used as arguments in the printf calls should be externalized in a document, and that document's path should be passed as parameter in the xdebug.ini.
That would be so great... on many websites i develop the xdebug output is unreadable, due to special page layouts. And because of the xdebug html output, reading the source page is quite painful.
A smaller feature would be a configuration parameter in xdebug.ini, that would switch output between plain text (with line feeds) or html.
Thanks for your attention.