WordPress at a glance
filter is not described

theme_root filter-hook . WP 1.5.0

Filters the absolute path to the themes directory.

Usage

add_filter( 'theme_root', 'filter_function_name_6380' );
function filter_function_name_6380( $theme_root ){
	// filter...

	return $theme_root;
}
$theme_root(string)
Absolute path to themes directory.

Where the hook is called

get_theme_root()
wp-includes/theme.php 562
return apply_filters( 'theme_root', $theme_root );

Where the hook is used (in WP core)

Does not used.