Dear List,

I'm confused by the result of the following example (see attached):

    \definefontfamily[face1][rm][gabriola][it={features:{default}}]
    \definefontfamily[face2][rm][gabriola][it={features:{default, effect={}}}]
    \definefontfamily[face3][rm][gabriola][it={features:{default, effect={width=1.0}}}]
    \starttext
   
    \startitemize[n, packed]
    \item \switchtobodyfont[face1]\it\dorecurse{100}{a b c }
    \item \switchtobodyfont[face2]\it\dorecurse{100}{a b c }
    \item \switchtobodyfont[face3]\it\dorecurse{100}{a b c }
    \stopitemize
   
    \stoptext

Could someone explain:
1. What does "effect" mean? Why does "effect={}" embolden the fonts even though nothing ({}) is given as arguments?
2. Similarly, what does "width" do? Why does "width=1.0" shrink the width of the line instead of doing nothing?

Thanks in advance.

Best,
Sylvain