FreeType

FreeType is a software font engine that is designed to be small, efficient, highly customizable, and portable while capable of producing high-quality output (glyph images).

FreeType 2 is released under two open-source licenses: BSD-like FreeType License and the GPL. It can thus be used by any kind of projects, be they proprietary or not.

Currently Factor uses FreeType to render fonts in the UI