For the moment, that would not be enforceable in respect to people with technical knowledge. Enforcing it would require authoritarian control and even China’s Great Firewall has way to circumvent it.

On the other hand, this is already far more difficult than you might think. You could not install such an app from a server authenticated with TLS because the TLS keys might be subverted - the certification chain has national institutions as the top certificate authorities. You would also not be able to install such an app on an Android phone because Google has decided it needs developer attestation to install apps in a way accesible to end users. You can run Linux now but if all that is taken seriously, your options to run Linux might become limited. E.g. you already can’t run many banking apps on phones with user-controlled OS software. Railway apps like the German one already don’t work. In future, you might not even be able to use a municipial library’s or bookstore’s website this way.

But more to the point, the real application case for this kind of civil rights is not some nerd kids which want to play DnD or minecraft on their own server or test their self-written IRC service. The real application case is what we see in the US, people being dragged out of their house and disappearing just because of their ancestry, how they look, being poor or the area they live in. They don’t have time to compile software or configure port-knocking protocols.

Somebody has called these systems of “democratic” mass surveillance uncovered by Snowden “Turnkey Dictatorship” . I for sure wish they would have been wrong.