Problem: Since some days you see more and more hits on a non existing browserconfig.xml and couldn´t explain that. The solution to fix that is however quite simple (read below).
With IE 11 Microsoft implemented a “Browser configuration schema reference” which is documented here. This forced the browser to search for a default browserconfig.xml (if not specified otherwise). If you now wish to remove the hits from your log (to clean it up) and do not wish to use that feature you need to define the following tag in your header section (might be the index.php from your template).
<meta name="msapplication-config" content="none"/>
It might take some days until this setting is used on all sessions due to some cached content (e.g. proxy server)