1.wp_version_check
Check WordPress version against the newest version.
The WordPress version, PHP version, and Locale is sent. Checks against the WordPress server at api.wordpress.org server. Will only check if WordPress isn’t installing.
2.wp_update_plugins
Check plugin versions against the latest versions hosted on WordPress.org.
The WordPress version, PHP version, and Locale is sent along with a list of all plugins installed. Checks against the WordPress server at api.wordpress.org. Will only check if WordPress isn’t installing.
3.wp_update_themes
Check theme versions against the latest versions hosted on WordPress.org.
A list of all themes installed in sent to WP. Checks against the WordPress server at api.wordpress.org. Will only check if WordPress isn’t installing.
4.wp_maybe_auto_update
Performs WordPress automatic background updates.
5.wp_scheduled_delete
Permanently deletes posts, pages, attachments, and comments which have been in the trash for EMPTY_TRASH_DAYS.
However, these are not easily visible to the user. Never fear because just like “there’s an app for that”, in WordPress, there’s a Plugin for that! – WP Crontrol (https://wordpress.org/plugins/wp-crontrol/)