wp-includes/class-wp-theme.php:1208Returns the URL to the directory of a theme's "template" files.
string public function get_template_directory_uri() { if ( $this->parent() ) { $theme_root_uri = $this->parent()->get_theme_root_uri(); } else { $theme_root_uri = $this->get_theme_root_uri(); } return $theme_root_uri . '/' . str_replace( '%2F', '/', rawurlencode( $this->template ) ); }Introduced in 3.4.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/class-wp-theme.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.