WordPress at a glance
filter is not described

get_the_tags filter-hook . WP 2.3.0

Filters the array of tags for the given post.

Usage

add_filter( 'get_the_tags', 'filter_function_name_623' );
function filter_function_name_623( $terms ){
	// filter...

	return $terms;
}
$terms(WP_Term[])
An array of tags for the given post.

Where the hook is called

get_the_tags()
get_the_tags
wp-includes/category-template.php 1131
return apply_filters( 'get_the_tags', get_the_terms( $id, 'post_tag' ) );

Where the hook is used (in WP core)

Does not used.