In computing, DLL (an abbreviation of 'Dynamic Linked Library') is a file extension for executable libraries. DLL files are commonly used by software programs to store parts of the executable code.

APK file extension is short for Androi Package. It is used to store information about Android deployment packages. APK files are usually used by Android and Google Play to deliver applications to Android devices.

PART extension is used by Mozilla Firefox to store partially downloaded files. Usually this file extension is given to files which are currently being downloaded. If you see PART files on your computer it means that either Firefox Mozilla is currently downloading something or that download failed in the middle.

The existence of two different file extensions for naming audio-only MP4 files has been a source of confusion among users and multimedia playback software. Since MPEG-4 Part 14 is a container format, MPEG-4 files may contain any number of audio, video, and even subtitle streams, making it impossible to determine the type of streams in an MPEG-4 file based on its filename extension alone. In response, Apple Inc. started using and popularizing the .m4a file extension. Software capable of audio/video playback should recognize files with either .m4a or .mp4 file extensions, as would be expected, as there are no file format differences between the two. Most software capable of creating MPEG-4 audio will allow the user to choose the filename extension of the created MPEG-4 files.

Direct Access Archive, or DMG, is a proprietary file format developed by PowerISO Computing for disk image files which supports features such as compression, password protection, and splitting to multiple volumes. It can be handled like a file just like other formats, such as an ISO image and BIN, but is currently only usable by PowerISO software. Popular disk image mounting programs such as Alcohol 120% and Daemon Tools currently do not support the mounting of DAA images.

PART extension is used by Mozilla Firefox to store partially downloaded files. Usually this file extension is given to files which are currently being downloaded. If you see PART files on your computer it means that either Firefox Mozilla is currently downloading something or that download failed in the middle.

BIN file is short for binary file. It is impossible to open BIN files in text editor because they consist of information in binary form which could only be enterpreted by computer applications or operating system. This extension is also associated with extension used for UNIX executable files.

You can open XLS file using Microsoft Excel application. Microsoft Excel is similar to other spread sheet applications that can store information that can be edited and viewed on several platforms. You can run Microsoft Excel and open XLS files on Mac and Windows through installed Microsoft Office applications.

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.

In computing, DOC or doc (an abbreviation of 'document') is a file extension for word processing documents; most commonly for Microsoft Word. Historically, the extension was used for documentation in plain-text format, particularly of programs or computer hardware, on a wide range of operating systems. During the 1980s, WordPerfect used DOC as the extension of their proprietary format.

SWF file extension is used to store Adobe Flash multimedia file format. SWF (pronounced “swiff”, short for “Shockwave Flash”) file format was developed by FutureWave Software Inc in 1995 and released as a storage format for FutureSplash Animator software on Windows and Mac OS.

HEIC is a new file format designed to store highly compressed photos and videos. HEIC and HEIF formats were developed by MPEG group and are currently adopted by multiple vendors including Apple and Microsoft.

In order to open CRDOWNLOAD file you need to know what exactly it contains. CRDOWNLOAD file extension means that the file download was started by Google Chrome but hasn't completed yet. Typically CRDOWNLOAD file extension is removed by Chrome once download is complete.