diff --git a/src/wp-includes/formatting.php b/src/wp-includes/formatting.php
index a07a020629..56a9c1edd0 100644
--- a/src/wp-includes/formatting.php
+++ b/src/wp-includes/formatting.php
@@ -3844,3 +3844,24 @@ function get_url_in_content( $content ) {
 
 	return false;
 }
+
+/**
+ * Returns the regexp for common whitespace characters.
+ *
+ * By default, spaces include new lines, tabs, nbsp entities, and the UTF-8 nbsp.
+ * This is designed to replace the PCRE \s sequence.  In ticket #22692, that
+ * sequence was found to be unreliable due to random inclusion of the A0 byte.
+ *
+ * @since 4.0.0
+ *
+ * @return string The spaces regexp.
+ */
+function wp_spaces_regexp() {
+	static $spaces;
+
+	if ( empty( $spaces ) ) {
+		$spaces = apply_filters( 'wp_spaces_regexp', '[\r\n\t ]|\xC2\xA0| ' );
+	}
+
+	return $spaces;
+}
\ No newline at end of file