Licence and updates — What a licence unlocks, what happens when one lapses, how updates arrive, and how to move a site between domains without losing an activation.
Importing a demo — Build a whole example publication in one press — what it installs, what it leaves alone, and what to do with it afterwards.
Constants and hooks — Everything you can set in wp-config.php, and the filters and actions worth knowing about.
When something is wrong — The dashboard that reads the whole install back to you, and the handful of problems that account for most of what goes wrong.