Well it’s hard to do without leaving a very clear trail. I assume most engineers want to keep their job and their income.

But programmers tend to use some form of a “versioning” system like git. This will record everyone’s changes to the codebase, when a change was made, what was changed, who changed it. And it allows you to go back and revert changes if something important broke. Very convenient for programmers, less convenient for sabotage.