This table contains a compact representation of a PostScript Type 1, multiple master, or CIDFont and is structured according to Adobe Technical Note #5176: "The Compact Font Format Specification," and Adobe Technical Note #5177: "Type 2 Charstring Format."
Existing TrueType fonts use a glyph index to specify and access glyphs within a font, e.g. to index the loca table and thereby access glyph data in the glyf table. This concept is retained in OpenType PostScript fonts except that glyph data is accessed through the CharStrings INDEX of the CFF table.