StarOffice Writer Document - Legacy (.sdw)
The SDW file extension stands for StarOffice Writer Document, used by the StarOffice Writer software for text documents. Introduced with StarWriter 1.0, SDW files were commonly used in the early 2000s. These files can be opened by modern office suites like Apache OpenOffice with legacy filters installed. SDW files are part of the evolution of document formats leading to today's more standardized formats like ODT.