.fil - File template
.application - ClickOnce deployment manifest file
.mobi - Mobipocket eBook Format
.mdf - Menu definition file
.x_t - Parasolid document
._3 - Audio Utility Tuningwrench compressed file
.3 - IBM Voice Type languages scripts Data file
.wmz - Windows Media Player skins file
file extension CUP - OzWin CompuServe access catalog library update file
File extension CUP description:
OzWin was a client program which was used to connect to the CompuServe Information Service. It was a GUI program that ran on the Microsoft Windows operating system. OzWin was born out of the earlier OzCIS program which was DOS based. OzWin allowed users to connect to CompuServe forums and batch download messages, files, and so forth from the server and then disconnect. They could then read the messages offline, and as well compose new messages and replies while offline. When they finished reading and composing messages, they could connect again to batch send all of the messages, as well as receive any new messages others had posted to the forums. This allowed users to batch upload and download messages and then work offline, minimising the time they were connected to CompuServe. This was important, since at that time, users were charged by the hour to connect to CompuServe, so remaining connected all the time was an expensive proposition and could quickly run up charges.