The IDN Navbar add-on provides address bar support for 'all' IDN's, including 'white-listed' TLD's (Top Level Domains) such as '.com', '.net', '.eu'.
Firefox has the ability to use IDN's for all TLD's but for security reasons has disabled it for certain ones. (i.e. '.com', '.net', '.eu').
스타벅스코리아.com is the IDN for Starbucks Korea.
Clicking on this link with default Firefox >= 3, the address bar will load the Punycode representation.
Clicking on the above link with this add-on installed, the address bar will load the IDN.
(as the screen-shots illustrate)
This add-on is meant to provide a safe(1) and easy way to enable IDN's. When an IDN is displayed in the address bar (which has been decoded from it's Punycode by this add-on) an 'IDN' icon will appear on the right side of the bar, clicking it will pop up an message showing the IDN and it's Punycode equivalent. (In other words if you see http://paypal.com and there is an IDN icon in the address bar something is very wrong! paypal.com is not an IDN)
IDN's are gaining popularity and there are bugs and support requests opened regarding this (IDN/Punycode) issue. Hopefully this add-on will be useful in addressing them, for the 'general population'.
Bug 542562 - international IDN domains (com, net,.. etc.) do not encode/decode the URL
When starts Firefox to support IDN's (Internationalized Domain Names)?
(1) Unproven statement. It's safer than tweaking settings in about:config