XcodeExplorer
XcodeExplorer is a quick and dirty Xcode4 plugin that allows you to watch and filter the various NSNotification events that are triggered as you use Xcode. This is useful if you are writing your own Xcode plugins and want to see how to hook into the Xcode workflow.
Once you install it into your Xcode4 plugins directory, it will create an Explorer menu item from whence you can open the notifications window.
Once opened, you can input a comma-seperated list of regular expressions of notification names that want to exclude. By default, it excludes all of the notifications starting with NS.
Click on the Start button, and it will start capturing any NSNotifications that are emitted by Xcode. Feel free to navigate around Xcode performing various actions, and click Stop once you are done.
The table in the window displays the notifications, and the results of invoking the description method on the notification’s object and userInfo properties. As you can see, the formatting is quite rough and ready, but it should give you a pretty good idea of what sorts of notifications may be available for your plugin.