There are 2 file types use the .XSF file extension:
1. InfoPath Form Definition File
File used by InfoPath, a program used for creating forms; specifies the content, properties, and structure of the form template (.XSN file); stored as one of the files inside of the XSN template; adheres to the InfoPath XSF schema (an .XSD file) published by Microsoft.
Most of the time XSF files are generated and maintained automatically by the InfoPath software. However, sometimes form developers manually edit XSF files to extend the functionality of the form templates.
Updated: June 1, 2012
2. Cal3D XML Skeleton File
Three-dimensional model file created using Cal3D, an open source character animation program; contains parent to child relationships between the characters skeletal bones (torso, legs, arms, etc); used for creating character motion.
XSF files store the skeleton data using XMl formatting, whereas Cal3D skeleton .CSF files use a binary format.
Updated: May 26, 2011