Fontconfig

Fontconfig (or fontconfig) is a free software program library designed to provide configuration, enumeration and substitution of fonts to other programs. Fontconfig was originally written and maintained by Keith Packard, and is currently maintained by Behdad Esfahbod.

Fontconfig is typically used on graphical Linux (and other Unix-like) desktops, such as Xorg and Wayland, where it remains an important part of handling fonts. However, it is also sometimes used on other platforms, notably including Windows versions of software that use Pango for laying out and rendering text, such as GIMP.