Amharic

[Hans Åberg]

Amharic does not display when using:
\header{
  composer = "Mulatu Astatke (ሙላቱ አስታጥቄ)"
}
Instead, showing a series of PRIVATE USE AREA-10FC18 U+10FC18.

On MacOS, there is a system font Kefa for Amharic.

So what is missing here?