The extension DIF identifies files in the Data Interchange format. This industry standard is for exchanging data between different applications, especially spreadsheets. It was developed by Software Arts for VisiCalc and is widely used today. Occasionally, the format is also referred to as Lotus DIF or Navy DIF. The file contains only the text, values, and formulas of the current worksheet.
It represents the standard export format of various spreadsheets and can also be opened with a text editor and can also be edited there.