Earlier quoted context omitted.
I think what they are describing there runs before the uninstall does it not? Pretty sure mine was after the uninstall completed, which is not possible since the app is already gone by that point.
There are actually networks of unrelated apps that listen for uninstalls. I was contacted by a company wanting to add their SDK to my apps, partly for this purpose. Uninstall activity is just another thing being monitored.
Thanks for chiming in. I didn't know this kind of company or business model existed, so now I will be more wary about installing seemingly benign apps. (I am not an app developer).