SYLK
From Just Solve the File Format Problem
SYLK (Symbolic Link) is a format devised by Microsoft for data interchange between applications, primarily spreadsheets. It has nothing to do with the "symbolic links" or "symlinks" used to tie multiple file paths to a single file in some operating systems including Unix-type systems.
SYLK is text-based, and is encoded in the native Windows code page (such as Windows 1252) of the system they are created on (rather than in Unicode as modern applications use).
Some of the "boilerplate articles" on sites that claim to document file formats by extension refer to .sylk or .silk files, but the official extension of this format is .slk (still under the influence of old-timey DOS thinking where extensions had to be 3 characters or less).
