On my openSuSE GNU/Linux box, I get different results.
Given font name: Emmentaler-13
Determined font file: /usr/share/fonts/TTF/mplus-1c-medium.ttf
Actual font in that file: mplus-1c-medium
Given font is present: #f
Given font name: Emmentaler-13
Determined font file:
/usr/local/share/lilypond/2.19.16/fonts/otf/emmentaler-13.otf
Actual font in that file: Emmentaler-13
Given font is present:
#t/usr/local/share/lilypond/2.19.16/fonts/otf/emmentaler-13.otf
Emmentaler-13
Given font name: Alegreya
Determined font file: /usr/share/fonts/TTF/mplus-1c-medium.ttf
Actual font in that file: mplus-1c-medium
Given font is present: #f
Given font name: Alegreya
Determined font file: /usr/share/fonts/truetype/Alegreya-Regular.ttf
Actual font in that file: Alegreya-Regular
Given font is present: #f/usr/share/fonts/truetype/Alegreya-Regular.ttf
Alegreya-Regular
Note that `ly:ttf-ps-name' returns the font's *PostScript* name. This
is *not* what fontconfig normally operates on (but see below).
Since FontConfig version 2.11 (released October 2013), however, it is
possible to search for PostScript names also. Example:
$ fc-match "Alegreya"
Alegreya-Regular.ttf: "Alegreya" "Regular"
$ fc-match "AlegreyaRegular"
arial.ttf: "Arial" "Normal"
$ fc-match ":postscriptname=AlegreyaRegular"
Alegreya-Regular.ttf: "Alegreya" "Regular"