It is called Brupt.
The search engine is pretty simple to use and seemingly has been around 2008. It is basically a Google based document search tool that lets you search for documents already indexed by Google.
Most of you must think that if we still have the Google Search Engine why use a new one. Moreover, there are atleast a hundred more search engines out there. So why Brupt?
Well, it is a fact that most of us use Google to search almost everything. But sometimes we do not get the required results for specific files like word documents, Powerpoint presentations, PDFs. Brupt effectively filters your search results and makes your search for a desired document file more efficient.
This document search engine comes in really handy for search engine users who are not aware of Google operators and their functionality. You can also create your own search engine based on the filter you specify. Click here to visit Google Custom Search and create your own with just a few clicks.
For now, Brupt seems to be a good job feeling the void for a good document search engine. I just hope it gains more popularity because it is simply sad if a good work of technology remains obscure for years.