This extension displays the RMB/NZD exchange rate retrieved from BOC.cn(Bank of China). The update interval can be configured. It always shows alerts when the BOC.cn website has a update since the last polling. The reason for scraping off BOC.cn is because Bank of China is almost the only venue where you can legally transfer money from China to New Zealand. Therefore, we display the exchange rates that BOC publishes for those people who need to wire money between China and New Zealand.
The source code can be obtained from the xpi file directly. It is under GNU LESSER GENERAL PUBLIC LICENSE. So feel free to use/modify it.