WordPress at a glance
filter is not described

prepend_attachment filter-hook . WP 2.0.0

Filters the attachment markup to be prepended to the post content.

Usage

add_filter( 'prepend_attachment', 'filter_function_name_9579' );
function filter_function_name_9579( $p ){
	// filter...

	return $p;
}
$p(string)
The attachment HTML output.

Where the hook is called

prepend_attachment()
prepend_attachment
wp-includes/post-template.php 1597
$p = apply_filters( 'prepend_attachment', $p );

Where the hook is used (in WP core)

Does not used.