SplineFont DataBase. These are FontForge s own personal font representation. The files are ASCII and vaguely readable, the format is described here. As of 14 May 2008 the format has been registered with IANA for a MIME type: application/vnd.font-fontforge-sfd.Other people use sfd too. (Unfortunately) Tops-10, on the Digital PDP-10 used sfd to mean Sub File Directory . Tops-10 made a distinction between top-level (home) directories, called user file directories , and sub-directories. TeX uses it to mean Sub Font Definition where a TeX sfd file contains information on how to break a big CJK or Unicode font up into small sub-fonts, each with a 1 byte encoding which TeX (or older versions of TeX) needed. Others...
Font Forge Glossary