3rd party application code remains on site even after removal in the apps section

Hello, I installed the “addthis” application in the control panel to a site at mustread.us - subsequently, I removed the app after trying it.
That was days ago. I’ve cleared the cache at Cloudflare, but still note that the site is making a call to the addthis application on pageload.
Is there a way to be certain that any “un-installed” applications are truly uninstalled all the way?

Thank you.

To be clear, the application is no longer “running” on the site after removal, i.e. the social buttons are not there any more, but when the page loads, it hangs a little still looking for addthis, as if there’s still some residual code that never got cleaned out on removal…

I’m not seeing any traces of Addthis. Could it be stuck in your browser’s cache?