I just acquired my first Firefox O/s powered device and to my utter amazement there was no way to synchronise contacts with Thunderbird. Not even an import. I can understand Samsung and other vendors "overlooking" this functionality. At least Samsung synchronised to Windows contacts. But the two products carry a common brand. Mozilla. So how about sharing the love and including Mozilla's mail client as well as Microsoft's. Firefox OS support only shows this https://support.mozilla.org/en-US/questions/1045611 synchronise view Google.
As a temporary solution, you could export your contacts in vCard format, thanks to this addon. Then, you can put the file on the SD Card and import it from there.  https://addons.mozilla.org/en-US/thunderbird/addon/thundersync/
Thanks Johan, I went the Google route... but filed this bug because I see this as a glaring omission. Android is tightly integrated to Gmail. IOS likewise is integrated quite well with other Apple products via iTunes if nothing else. Mozilla however chose to release their product with no integration.