It doesn't use it in the browser but it does use it for tools relating to SPDY. ...

It doesn't use it in the browser but it does use it for tools relating to SPDY. See:

Regardless, neither OpenSSL or NSS have NPN in a release version. NSS doesn't seem to have merged the patch yet: https://bugzilla.mozilla.org/show_bug.cgi?id=547312

bzbarsky on April 12, 2011 [–]

Ah, indeed. Thanks for the pointer!