Thanks for the answers! I think the main point that is still unclear is debugging. What you mentioned is basically what I have been testing. When I try to run the app extension with the debugger attached and select the owning app as the Host App, the debugger automatically detaches from the app extension when the app crashes. The only way I was able to make it work was by selecting a different Host App, for example Safari or Photos, instead of the app that owns my Crash Reporter Extension. Even then, in around 90% of cases, after hitting the breakpoint, the debugging session stops a few seconds later.

(@Systems Engineer answering here as I cannot do it with the "Add Comment"). I agree with you that MetricKit will probably help here (and also state reporting api) As far as I know Xcode Organizer is only accessible to the app developer. So we (the SDK), cannot get that information directly (we know it's useful, we just cannot get it) Regarding lower-level APIs, is there anything similar to extracting ri_billed_energy from rusage_info_current, or anything along those lines, that could help narrow the attribution down to my SDK or to specific functions in my code?