They still need to choose when to do that though. When I prompt the program to e.g. alter a bash script in a specific way or to recite a longer known text it can't go round and randomly exchange tokens. It has to somehow define what is a simple repeated text from a different origin and what is a novel generation.

I am wondering how that applies to newly generated code.

Odd variable naming? Stylistic choices that are watermarked?

Or as someone else noted further down in the comments, it could be more subtle:

Between the first and second most likely choice, in certain positions it will consistently choose in a certain way.