Imagine you work in a modern software house and you get one of these ... and here I mean you, not your boss, not your coworkers, the govt knocks on your door and demands you put a back door in the thing you are working on at work ...
So you write the code ... how do you write the unit test? how do you get it past the code review? the mandatory QA tests? ... all these things are designed into our modern software design processes essentially designed to stop bad stuff like this happening ... what happens when you get caught? you lose your job, get blacklisted in the industry, after all you can't tell them the govt made you do it (on your CV/resume trying to explain why you were fired)
Equally say you run a big open source software project and you have valued contributors from Australia, people you trust and depend on ... what do you do? refuse them commit right? explicitly audit their every checkin? ask them to move on?
Suppose you buy closed source code from Australia .... you can't trust it in any way, even if you trust the company any one of their employees may have been asked to suborn the code you've paid good money for ... any smart purchaser is simply going to put Aussie software on the "do not purchase" list .....
So how do I find out which software on Android Play is written in Oz?