If you get into an issue whereby trying to debug the receipt processing of your App Store App is constantly being rejected as the “App is damaged”. I may have found the reasoning.
12:06:33.078 E **storeuid** [3797:65e2d] [com.apple.commerce:CommerceKit] <ReceiptRefreshRequest: 0x7f88d0cc27b0>: Error fetching receipt for com.ohanaware.HDRtist - Error Domain=NSCocoaErrorDomain Code=512 "The file “_MASReceipt” couldn’t be saved in the folder “Contents”." UserInfo={NSFileOriginalItemLocationKey=file:///Volumes/rowlands/Applications/HDRtist.app/Contents/_MASReceipt, NSURL=file:///Volumes/rowlands/Applications/HDRtist.app/Contents/_MASReceipt, NSFileNewItemLocationKey=file:///System/Library/Caches/com.apple.receiptInstaller/HDRtist.app/_MASReceipt/, NSUnderlyingError=0x7f88d2b4abb0 {Error Domain=NSCocoaErrorDomain Code=512 "The file “_MASReceipt” couldn’t be saved in the folder “HDRtist.app”." UserInfo={NSURL=file:///System/Library/Caches/com.apple.receiptInstaller/HDRtist.app/_MASReceipt/, NSFilePath=/System/Library/Caches/com.apple.receiptInstaller/HDRtist.app/_MASReceipt, NSUnderlyingError=0x7f88d2b5e6c0 {Error Domain=NSPOSIXErrorDomain Code=18 "Cross-device link"}}}}
If you manually move the app into the Psuedo Applications folder /Applications/ (I tried to script it and failed), it then works. I am not sure if I am doing something wrong or not, I don’t recall receipt debugging being this hard, but also this is the first time I’m using Catalina to do it with.