For starters the terms are incorrectly used.
Authorship is always from the moment of creation. Then, when the project is joined by other people - it may be eroded. But just to give up authorship in legal terms is impossible. Well if you are anonymous, of course.
Come to me uncle in uniform and say that it's important, they need a backdoor and access to personal data (I do not save, but now needs to preserve and pass on to them). To cooperate I have no desire to.
This is a different sort of thing.
If you system to sell/rent and there is a corresponding law - or have to build or break this business. Well, or run as the actor with his Telegram.
Is it possible to voluntarily withdraw from the law and responsibility for the project to be innocent?
Responsibility for what?
If you have some Trojan, then it will not work.
If something like messenger, you just block. Actually all this thing for you which can be uncomfortable if you have big and popular project.
Well, that is how you will refuse, but that project alive?
Well publish the source code.
And the server will be locked and project will die anyway.
Option just to forget the password from the relevant accounts are not very suitable, because they tied a whole bunch more, my life in the end. Yes, then go and prove that I forgot, and do not hold back.
It all depends on the importance of the project.
If it's wildly important - for example, the payment system, through which are billions around the world - you wouldn't want to give up.
If you project to drop, it is likely that it will be bent.
But in such an unimportant project no one is interested to get you a backdoor.