Plugins, themes and core
The site's inventory, and the one-at-a-time changes made from it.
Plugins
The Plugins page lists what the site reported: name, version, whether it is active, and whether an update is available. Sync asks the site again. From the list an administrator can activate or deactivate one plugin or several, and update a plugin that has an update on its own — outside an update round, without the round's backup and checks. Use an update round for anything you would want to be able to roll back.
The worker refuses to delete itself through this page.
Themes
The same for themes: what is installed, which is active, what has an update. Activate, deactivate, update.
Core
The site's WordPress version and the version available. Updating core from here updates it on its own; an update round does it with a backup first and the site's pages checked afterwards.
How current the list is
Each page shows when the platform last received that dataset from the site and over which channel — the platform's own read, or the site's report. A list that is older than a day is marked stale, and the age is shown rather than hidden; a site the platform cannot reach keeps reporting on its own schedule, so its list stays current anyway. Connection problems covers a list that stops updating.