GADGET, Windows Gadget (.gadget)
The GADGET Executables file format
Introduced in Windows Vista and expanded for Windows 7, Microsoft had developed its own little programs (called gadgets). These programs could run within he sidebar of the respective operating system's version. The programs include search tools, games and other utilities. They are saved in their very own file format with the GADGET file extension. In newer versions of Windows, these gadgets aren't used anymore and the GADGET file format is regarded as discontinued.
Technical details of GADGET files
GADGET files contain different source code files like CSS, JS or HTML. Other web and developer files can be contained as well. The GADGET file stores them all within a ZIP archive. Due to their nature, GADGET files can be easily renamed to ZIP and opened with a decompression software. Windows provided a number of gadgets of their own, but user could create functioning GADGET files as well.