In computing, RAR is a proprietary file format for data compression and archiving, developed by Eugene Roshal (hence the name RAR: Roshal ARchive). The filename extension used by RAR is .rar. If a RAR-archive is broken into many smaller files (a multi-volume archive), as is often the case when it was distributed on Usenet, then those smaller files carry the extensions .rar, .r00, .r01, .r02 etc. and most unrar programs reconstruct the whole archive when provided with the .rar file.

A file with the extension .p7m (digitally encrypted message) stores encrypted e-mail message. P7M contains both the messages and any attachments in it. Encrypted P7M files are used to prevent unauthorized access to e-mails

CFG file extension is used by files storing various kinds of configuration information. CFG files are frequently referred to as configuration files. Configuration files can store various parameters, settings and start-up information used by applications or operating system.

DIAGCAB file is used by the Microsoft Support Diagnostic Tool to deliver diagnostic tools and software fixes to consumer computer.

LNK files are commonly known as Windows shortcuts. They are used to refer to local files or remote urls. To view information in LNK file in Windows you can press right mouse button on a LNK file and select Properties from popup menu.

JNLP is short for Java Network Launching Protocol. This format is used by Java to download and launch applications over the network. JNLP applications typically don't run from user internet browser.

The Portable Document Format (PDF) is the file format created by Adobe Systems in 1993 for document exchange. PDF is a fixed-layout format used for representing two-dimensional documents in a manner independent of the application software, hardware, and operating system. Each PDF file encapsulates a complete description of a 2-D document (and, with Acrobat 3-D, embedded 3-D documents) that includes the text, fonts, images, and 2-D vector graphics that compose the documents.

APK extension is used to deliver and install application software and middleware onto Google Android system. APK file contains compiled Android application code and all resources which are required by this code.

AI file extension is used by files produced by Adobe Illustrator. AI is a vector image format which means it stores graphics information as a set of geometrical figures with their coordinates, sizes and transformations.

CRDOWNLOAD is chrome partially downloaded file. Usually such file cannot be recovered since only part of it was downloaded. You need to visit website with download again and re-download it.

TMP files are used to store temporary information. Typically these files are stored only while information in them is needed by an application or operating system and are deleted as soon as this information becomes obsolete.