font missing in firefox

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

Hello,
I noticed that my firefox on NetBSD is not displaying some fonts.
For example https://www.lip6.fr/?LANG=en on the top right there are
links to change language, link to webmail and to intranet. These links are
UTF-8 characters that should show some icons, on linux they show up properly
but on NetBSD (10-beta) it just display a rectangle with some hex in it.
It's possible I'm missing some fonts on my install but from what I understood,
firefox should download them. The debugger shows that the font used it
"opensans-bold", and I didn't find a package for this.
Any idea ?

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--