So, how exactly would anyone get a back door past code review? There are practices and processes that make this infeasible regardless of the Australian Governme

So, how exactly would anyone get a back door past code review? There are practices and processes that make this infeasible regardless of the Australian Government's belief they can coerce anyone. Every company I've felt have been worth working for in the past 10 years have had rigorous code review practices that would obstruct my ability to integrate any code without oversight. So... how?