WordPress at a glance
filter is not described

the_tags filter-hook . WP 2.3.0

Filters the tags list for a given post.

Usage

add_filter( 'the_tags', 'filter_function_name_2113', 10, 5 );
function filter_function_name_2113( $tag_list, $before, $sep, $after, $id ){
	// filter...

	return $tag_list;
}
$tag_list(string)
List of tags.
$before(string)
String to use before tags.
$sep(string)
String to use between the tags.
$after(string)
String to use after tags.
$id(int)
Post ID.

Where the hook is called

get_the_tag_list()
the_tags
wp-includes/category-template.php 1121
return apply_filters( 'the_tags', get_the_term_list( $id, 'post_tag', $before, $sep, $after ), $before, $sep, $after, $id );

Where the hook is used (in WP core)

Does not used.