WordPress at a glance
action is not described

unmature_blog action-hook . WP 3.1.0

Fires when the 'mature' status is removed from a blog.

Usage

add_action( 'unmature_blog', 'action_function_name_1823' );
function action_function_name_1823( $blog_id ){
	// action...
}
$blog_id(int)
Blog ID.

Where the hook is called

update_blog_details()
unmature_blog
update_blog_status()
unmature_blog
wp-includes/ms-blogs.php 357
do_action( 'unmature_blog', $blog_id );
wp-includes/ms-blogs.php 1037
do_action( 'unmature_blog', $blog_id );

Where the hook is used (in WP core)

Does not used.