This post will help you out with searching .mpp (Microsoft project) file in SharePoint.
So lets get started :)
1. First of all we have to add .mpp extension to our search service application file types.
2. Go to Search Service Application manage page > Click on File types.
3. Click on New File Type. Enter extension .mpp and click OK
5. Most important part you have to do an index reset and then full crawl of local SharePoint sites .
6.Once after the completion of Crawling. You can try to search for .mpp file in your sites
Below are the search result for Microsoft project file (.mpp)
Happy SharePointing :)