User Profile

Hi,I tried to show thumbnails for my custom file type in a document based app. I already looked at the Particles example project and structured my app like this. But I still can't get the thumbnails work for my files. Breakpoints and logging also doesn't work for me in the extension.What I've tried (using Xcode 11.4.1):Create a thumbnail extensionSet the UTI in the Info.plist to the corresponding UTI that I used in the appSet the deployment target to iOS 13Link the QuickLookThumbnailing.framework to the extension and the appRun on a physical iPad and iPhone (although I don't want to support iPhones at the end)But unfortunately nothing works. No matter what I try, the file in the document browser just shows the app's icon.Please help me before I'm going crazy 😕