Uninstalling macOS App Extensions from System Preferences

I'm a developer, but it is more of a user-centric question.

How can one "unregister" a Finder Sync (or any other, presumably) OS X / macOS App Extension so that it disappears from System Preferences > Extensions?

I've removed the app that's hosting it (FinderSyncTest), but it still shows here:

Solution 1:

I found my extensions in:

/System/Library/PrivateFrameworks/ShareKit.framework/Versions/A/PlugIns

Delete FinderSyncTest.appex, restart Finder, and it should be gone.

Solution 2:

Another answer in addition to my previous one: if your extension is actually runnable (i.e.: it doesn't crash when started via System Preferences -> Extensions), find the extension in your Activity Monitor, double click the process, then go to the "Open Files and Ports" tab. You'll see the path of your extension listed.

Solution 3:

Did you create this extension yourself?

I found that after creating, building, and testing an extension I created that there was some data that lives here:

/Users/$USER/Library/Developer/Xcode/DerivedData

that I needed to blow away and then relaunch the Finder (which can be done with Force Quit) to get the extension to "die"