Turns out centered-window-mode isn't in any ELPA repo. Was it removed? I'm not sure, so it's now fetched directly from its github repo.
lang/org's initialization process is now split up into hooks on org-load-hook. This approach is cleaner and easier to customize. I also removed the escape binding in org-agenda-mode-map, as the popup system makes it redundant.
after! org is more reliable than org-load-hook.
