Unknown handler causing 404 errors

Hi,

Recently I've noticed a number of 404 errors being reported in Google Analytics by users attempting to access - '/handlers/download.ashx'.

I do not have such handler implemented in the code and was wondering if this is an Episerver handler?

From the IIS log I can see the following:

GET /Handlers/Download.ashx Mozilla/5.0+(compatible;+DotBot/1.1;+http://www.opensiteexplorer.org/dotbot,+help@moz.com)

Has anyone seen this before? If so, my question is if this is Epsierver's handler?

Thanks for help.

Jakub