This mirrors my experience working at a company that achieved similar results on some of its internal products.
The very biggest difference between working there and working anywhere else, is that developers spent only a tiny fraction of time actually writing code.
The biggest chunk of it was spent on peer review. Every change required sign-off from everyone on the immediate team, and, if it was being made to a component that other teams interacted with, they'd also have members reviewing the changes. And, as a newcomer, I found the reviews to be brutal. Over time, though, I came to recognize that what originally felt like others getting all up in my business about pedantic little variable naming issues was actually everyone having my back about legitimate maintainability concerns.
Next biggest chunk was spent on planning - understanding requirements, talking over changes with anyone who might be impacted by them, etc.
The second biggest difference was just how fast we could move. I think a lot of that came from a certain "wei wu wei" that was attributable to the deep understanding of the systems we were working on that developed out of all that time with our hands off our keyboards.
Allow me the vice of inserting a mangled Hitchhiker's quote here: "If human beings don’t keep exercising their [fingers], he thought, their [hands] probably seize up. After a few months’ consideration and observation he abandoned this theory in favor of a new one. If they don’t keep on exercising their [fingers], he thought, their brains start working."