On Mon, Oct 1, 2018 at 7:56 PM Ulrike Fischer <news3@nililand.de> wrote:

>
> For what do you reserve the space in the PUA?
>

 http://www.pragma-ade.nl/general/manuals/fonts-mkiv.pdf
page 32 of the document :

As we already mentioned in a previous chapter, in ConTeXt we use Unicode
internally.
This also means that fonts are organized this way. By default the glyph
representation
of a Unicode character sits in the same slot in the glyph table. All
additional glyphs, like
ligatures or alternates are pushed in the private unicode space. This is
why in the lists
shown in the figures the ligatures have a private Unicode number.

-- 
luigi