How to locate extensions in list of macOS system settings?

I am working on a macOS file provider extension. Sometimes it cannot register itself (or more precisely its file provider domains) correctly due to some XPC issues with the NSFileProviderManager. Then I try to get a clean environment again. 1. I completely erased Xcode's DerivedData. 2. I emptied the trash because macOS does not care about the locations in this regard and loads extensions from there, too. 3. I removed all of the extensions file provider domains from the side bar in Finder. Looking for my extension in pluginkit yields no results by running this command:

$ pluginkit -vvvvmi 
  (no matches)

It also does not appear in the full list when leaving out the explicit identifier specification. **Still it appears in the list of the system settings! Where does this come from and how to reset it?** I can enable and disable them in the system settings. They even survive a reboot. And in macOS' Console.app I continuously see entries about the file providers displayed as "SomeProduct" and "Provider" here along their bundle identifiers. It appears like I messed up fileproviderd. I considered this more appropriate for this StackExchange site rather than StackOverflow because it is not directly related to programming. Also [these answers](https://apple.stackexchange.com/q/152541/58460) unfortunately did contain a solution. I also wrote a feedback in feedback assistant but according to my experience that is unlikely to be heard.