Microsoft Corporation File Extensions: A Complete Guide

File	Description
.%2401	MS-DOS pipe file
.%2402	MS-DOS pipe
.%2404	MS-DOS pipe
.%24ol	MS-DOS pipe
.%24o1	MS-DOS pipe
.%2405	MS-DOS pipe file
.hl%24	MS-DOS compressed help document
.pi%24	Microsoft compressed PIF program information
.emsixbundle	Encrypted MSIXBUNDLE package
.emsix	Encrypted MSIX package
.eappxbundle	Encrypted APPXBUNDLE package
.%21%40%21	Microsoft Windows backup of WIN.INI
.wa%7E	Microsoft Address Book data
.f%2Bdb	Microsoft FoxPro database
.%2403	MS-DOS pipe
.%7Ebt	Microsoft Windows update directory
.3%7E6	Microsoft Windows 3.x system data
.b%7Ek	Microsoft Windows 3.x data
.appinstaller	UWP App Installer file
.c%23	Microsoft Visual C# data
.c%2B%2B	C++ source code
.asp%2B	ASP.NET ASP+ file
.%24efs	Encrypted EFS data
.as%24	Microsoft Word temporary file