20 year veteran software engineer here
Dominion makes a software product. They sell it.
They have customers. Customers have needs.
Customers request features. Dominion creates the feature, adds it to a version roll out, and documents it in its user manual.
Sounds kinda normal right?
It is.
But what if the feature requests, not illegal or shifty on their own, were intended to fuck with the vote totals. For example features around "system tests" or network updates, or system keys, on an on an on, on the surface, don't look shady, but a group of even unrelated features can create a pathway to modify the vote when used in concert.
It's a way to create plausible deniability. The company can shrug their shoulders, the admins can do the same, and a few people that understand how to rig the machine do it.
The key to this is making sure the system doesn't log the pathway to modify the vote. For example, you don't log when a system test takes place so that it looks like votes were legitimately logged.
By designing the system to be just cloudy enough, you can create a very difficult to detect, yet massive fraud.