wpmu_delete_blog_upload_dir
Filter Hook: Filters the upload base directory to delete when the site is deleted.
Source: wp-admin/includes/ms.php:140
deleted_blog
Action Hook: Fires after the site is deleted from the network.
Source: wp-admin/includes/ms.php:184
wpmu_delete_user()
Function: Delete a user from the network and remove from all sites.
Source: wp-admin/includes/ms.php:202
wpmu_delete_user
Action Hook: Fires before a user is deleted from the network.
Source: wp-admin/includes/ms.php:230
upload_is_user_over_quota()
Function: Check whether a site has used its allotted upload space.
Source: wp-admin/includes/ms.php:278