WordPress at a glance
filter is not described

attachment_fields_to_edit filter-hook . WP 2.5.0

Filters the attachment fields to edit.

Usage

add_filter( 'attachment_fields_to_edit', 'filter_function_name_4654', 10, 2 );
function filter_function_name_4654( $form_fields, $post ){
	// filter...

	return $form_fields;
}
$form_fields(array)
An array of attachment form fields.
$post(WP_Post)
The WP_Post attachment object.

Where the hook is called

get_attachment_fields_to_edit()
get_compat_media_markup()
wp-admin/includes/media.php 1310
$form_fields = apply_filters( 'attachment_fields_to_edit', $form_fields, $post );
wp-admin/includes/media.php 1670
$form_fields = apply_filters( 'attachment_fields_to_edit', $form_fields, $post );

Where the hook is used (in WP core)

wp-admin/includes/media.php 2040
add_filter('attachment_fields_to_edit', 'media_post_single_attachment_fields_to_edit', 10, 2);
wp-admin/includes/media.php 2256
<?php add_filter('attachment_fields_to_edit', 'media_post_single_attachment_fields_to_edit', 10, 2); ?>
wp-admin/includes/media.php 2524
<?php add_filter('attachment_fields_to_edit', 'media_post_single_attachment_fields_to_edit', 10, 2); ?>
wp-admin/async-upload.php 61
add_filter('attachment_fields_to_edit', 'media_single_attachment_fields_to_edit', 10, 2);
wp-admin/async-upload.php 65
add_filter('attachment_fields_to_edit', 'media_post_single_attachment_fields_to_edit', 10, 2);
wp-admin/media.php 65
add_filter('attachment_fields_to_edit', 'media_single_attachment_fields_to_edit', 10, 2);