diff --git a/wp-includes/canonical.php b/wp-includes/canonical.php
index a799c5c2d3..2d776e8707 100644
--- a/wp-includes/canonical.php
+++ b/wp-includes/canonical.php
@@ -57,8 +57,8 @@ function redirect_canonical( $requested_url = null, $do_redirect = true ) {
 		}
 	}
 
-	if ( is_admin() || is_search() || is_preview() || is_trackback()
-		|| is_favicon() || ( $is_IIS && ! iis7_supports_permalinks() )
+	if ( is_admin() || is_search() || is_preview() || is_trackback() || is_favicon()
+		|| ( $is_IIS && ! iis7_supports_permalinks() )
 	) {
 		return;
 	}
@@ -655,8 +655,10 @@ function redirect_canonical( $requested_url = null, $do_redirect = true ) {
 		$redirect['path'] = trailingslashit( $redirect['path'] );
 	}
 
-	// Remove trailing slash for sitemaps requests.
-	if ( ! empty( get_query_var( 'sitemap' ) ) || ! empty( get_query_var( 'sitemap-stylesheet' ) ) ) {
+	// Remove trailing slash for robots.txt or sitemap requests.
+	if ( is_robots()
+		|| ! empty( get_query_var( 'sitemap' ) ) || ! empty( get_query_var( 'sitemap-stylesheet' ) )
+	) {
 		$redirect['path'] = untrailingslashit( $redirect['path'] );
 	}
 
@@ -682,11 +684,6 @@ function redirect_canonical( $requested_url = null, $do_redirect = true ) {
 		$redirect['host'] = $original['host'];
 	}
 
-	// Even if the permalink structure ends with a slash, remove slash robots.txt.
-	if ( is_robots() ) {
-		$redirect['path'] = untrailingslashit( $redirect['path'] );
-	}
-
 	$compare_original = array( $original['host'], $original['path'] );
 
 	if ( ! empty( $original['port'] ) ) {
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 573f2b6834..7fdecc472d 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.5-alpha-48165';
+$wp_version = '5.5-alpha-48166';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.