This format isn't that strange.

git-svn-id: https://develop.svn.wordpress.org/trunk@19688 602fd350-edb4-49c9-b593-d223f7449a82

wp-includes/script-loader.php

@@ -416,8 +416,7 @@ function wp_default_scripts( &$scripts ) {
  * @param object $styles
  */
 function wp_default_styles( &$styles ) {
-	// This checks to see if site_url() returns something and if it does not
-	// then it assigns $guess_url to wp_guess_url(). Strange format, but it works.
+
 	if ( ! $guessurl = site_url() )
 		$guessurl = wp_guess_url();