The postmortem is the only honest training material the team will ever have.
[ trace // field response ]
Every incident is curriculum. The postmortem is the textbook chapter. The blameless retrospective is the seminar. The fix is the homework. Teams that treat incidents as embarrassments to be minimised are throwing away the most expensive training material they will ever pay for.
Write the postmortem as if you are teaching the next engineer who has not been hired yet. They will read it. Most of what they know about the system will come from documents like this one.
Treat the archive of incidents as institutional memory. It is the closest thing the team has to one.