Each one exists to answer a question someone will actually ask.
Context, container and component views, each derived from the code and each traceable back to it.
Why the system is the way it is: the decision, the alternatives, and what it cost. The document that saves the next person a month.
The flows that matter, drawn as they actually execute, including the error paths people forget to document.
What to do to release, and what to do when the release goes wrong — written to be followed by someone tired and alone.
Every API and integration point, what it promises, who depends on it and what breaks if it changes.
Where things run, what to check when they misbehave, and which alarms mean something.
Describe the situation in your own words and see the procedure — and its cost — before you spend anything.