muplugins_loaded
Action Hook: Fires once all must-use and network-activated plugins have loaded.
Source: wp-settings.php:367
update-custom_{$action}
Action Hook: Fires when a custom plugin or theme update request is received.
Source: wp-admin/update.php:394
admin_enqueue_scripts
Action Hook: Enqueue scripts for all admin pages.
Source: wp-admin/admin-header.php:118
wp_mail_original_content
Filter Hook: Filters the original content of the email.
Source: wp-mail.php:193