What is "sfnt"

SFNT is a font file format which can contain other fonts, such as PostScript, TrueType, OpenType, Web Open Font Format (WOFF) fonts and other. SFNT stands for spline font or scalable font, and was originally developed for TrueType fonts on the Macintosh and used by Apple Computer's QuickDraw. SFNT was named after the resource tag the Macintosh used internally to track font data.

Many existing font formats are based on the table-based SFNT format, such as TrueType, OpenType and Open Font Format, Web Open Font Format (WOFF), SIL Graphite and many other.

SFNT is flexible, extensible and offers an opportunity to introduce additional table structures when needed, in a way that would not affect existing font rendering engines and text layout implementations.