Of course you can delete transactions with the UI, perhaps many at a time, but I had 23,000 transactions to remove and the UI couldn't handle deleting them in that kind of bulk. It would lock up/crash. The only way to restore it to its virgin state was to just trash the store.db file.

Submitted as FB9790739. Thank you!

It is a Mac Catalyst app. The app runs on macOS 12, it does not require an M1.

I was able to track down the files in question, in case anyone else in the future needs to know. For StoreKit testing on Mac catalyst, check the directory: ~/Library/Caches/com.apple.appstoreagent/Octane The sqlite file store.db contains a table octane_transaction with the transactions in question, and I was able to delete my 23,000 test transactions from it.