LilyPond Serif/Sans Serif/Monospace Text Fonts?

[Abraham Lee]

Greetings, Dev Team!

I was just browsing through some of the latest code (in scm/font.scm) and I
noticed that the default text font names are now LilyPond Serif, LilyPond
Sans Serif, and LilyPond Monospace. Do such fonts actually exist or are
these just place holders? It looks like the fontconfig allows for a
fallback fonts anyway. It's not a big deal. I was just curious. Looks like
Masamichi Hosoda made these changes.

http://git.savannah.gnu.org/gitweb/?p=lilypond.git;a=commit;h=28f58ecc2271956e9377dc61e5135ce3ade4abbd

Thanks for everything you all do to make this program what it is today!

- Abraham