How to know about any file format or extension ? 

Unknown file format?
When we are browsing internet or using various types of application, we finds files with unknown extensions. If we didn’t identifies the file we think, is this virus?, malware or something that can get me in trouble?. There are many solutions if you find’s some file or files with unknown file format. You can find out what applications should open this type of files, how important file to us and many more. Here are Solutions. :)
Web links
1. File extension seeker (A search engine too)
5. Filext
7. Wotsit