The other issue shown by examples 23, 24, and 26 is the limited glyph range of the current Type1 fonts that are being used with this device. Those glyphs are adequate for English text and basic Math symbols, but that is about it. So it would be useful to move to the TTF fonts instead which literally have tens of thousand glyphs available. The libharu TTF font support requires specifying the full path of TTF font file name which is a very clumsy and laborious way to specify fonts, and a more refined procedure involving fontconfig would be more convenient for the user at the relatively small expense of adding fontconfig (available on all platforms) to the dependencies of the pdf device.