To put it in perspective, Mozilla has no mobile platform and is crying for relevance.
Apple -> iOS/WebKit Google -> Android/WebKit Mozilla -> ???/Fennec
By getting desktop browsers to implement telephony and other collaboration APIs, I'm sure their hope is to get mobile browsers to likewise expose the precious voice and video APIs of the mobile handsets. And perhaps by doing this, lines between browsers on mobile devices are blurred to where Fennec has a role.