2.1.1091 Part 1 Section 220.127.116.11, embeddedFontLst (Embedded Font List)
a. The standard states that the font data is referenced within the embeddedFont element.
PowerPoint further requires that the typeface of each embeddedFont element shall be unique.
b. The standard states that the embeddedFontLst element specifies a list of fonts that are embedded within the corresponding presentation.
PowerPoint further requires that all of the fonts specified in this list shall be used in this presentation.