I've never seen a .3fg file before, what kind of file is that?

Most of the time you don't see those little letters at the end of a file, indicating what type of file it is, because your operating system already knows what program is affiliated with it and does not need to show you. However, everyone will come across a file that they do not have the program to open it with, and do not even know what type a program it is associated with. That is where file-extension-library.com comes in handy. They are creating a database of the different types of file extension and what type of files they are. What the heck is a .bup file extension? well simply clicking on the link from the main site I now know that it is a file that it is used in creating a backup on DVD's. Nice, simple and easy explanations of all the extensions helps to understand what type of program you are looking for to open the file. This site is in my bookmarks for future reference, and should be in yours as well.