I am struggling to prove to an auditor that no code was moved without an approva

I think the idea of mentioning the deletion.log is that if there's no entry there showing the deletion of the news feed event then you're proving that whatever is in the news feed is what really happened.

If you have the approval email and the post on the news feed then that proves the code was moved with the approval.

You should be able to match all approvals with IMPORT entries in the news feed. If they claim the news feed entries can be deleted, you can explain that those deletions get logged in deletion.log. That's how you'd know if there wasn't any approval, people trying to hide the import can be caught through the deletion.log since it captures deletions of news feed too.

I think the idea of mentioning the deletion.log is that if there's no entry there showing the deletion of the news feed event then you're proving that whatever is in the news feed is what really happened.

If you have the approval email and the post on the news feed then that proves the code was moved with the approval.

You should be able to match all approvals with IMPORT entries in the news feed. If they claim the news feed entries can be deleted, you can explain that those deletions get logged in deletion.log. That's how you'd know if there wasn't any approval, people trying to hide the import can be caught through the deletion.log since it captures deletions of news feed too.