WordPress at a glance
action is not described

manage_media_custom_column action-hook . WP 2.5.0

Fires for each custom column in the Media list table.

Custom columns are registered using the 'manage_media_columns' filter.

Usage

add_action( 'manage_media_custom_column', 'action_function_name_6012', 10, 2 );
function action_function_name_6012( $column_name, $post_id ){
	// action...
}
$column_name(string)
Name of the custom column.
$post_id(int)
Attachment ID.

Where the hook is called

WP_Media_List_Table::column_default()
wp-admin/includes/class-wp-media-list-table.php 592
do_action( 'manage_media_custom_column', $column_name, $post->ID );

Where the hook is used (in WP core)

Does not used.