Just the results of a name lookup Rated 2 out of 5 stars
This extension disappointingly does nothing more than list the records associated with the site's hostname, with the first record highlighted. It provides no indication of what IP your browser is talking to.
A hostname lookup might be enough information to guess if a site is IPv6-enabled ~80% of the time, but unfortunately sites with AAAA records aren't always actually listening on that IPv6 address. But this extension still shows the IPv6 address even if Firefox has had to fallback to a site's IPv4 address because the IPv6 address isn't up, or isn't running a webserver.
It also just highlights the first record in a round-robin RRSet, even if Firefox has done failover to another address in that RRSet.
The interface is nice and simple, a button with the current IP. A large assortment of functions are available on the address, though the difference between the left-click and right-click menus seems minor, they could just be combined into a single menu. It also allows you to move the button around via Firefox's toolbar "Customize", a very nice feature (though you seem to lose the ability to open the menus if you move it out of the status bar).
All in all, it would be a very nice addition if it actually showed information about your current connection. But as it is, it's basically just a shortcut to running 'dig' or 'nslookup' on every site you visit, and functionally just as external to the browser.