Index: src/wp-content/themes/twentyfifteen/inc/customizer.php
===================================================================
--- src/wp-content/themes/twentyfifteen/inc/customizer.php	(revision 30275)
+++ src/wp-content/themes/twentyfifteen/inc/customizer.php	(working copy)
@@ -17,8 +17,8 @@
 function twentyfifteen_customize_register( $wp_customize ) {
 	$color_scheme = twentyfifteen_get_color_scheme();
 
-	$wp_customize->get_setting( 'blogname' )->transport         = 'postMessage';
-	$wp_customize->get_setting( 'blogdescription' )->transport  = 'postMessage';
+	$wp_customize->get_setting( 'blogname' )->transport        = 'postMessage';
+	$wp_customize->get_setting( 'blogdescription' )->transport = 'postMessage';
 
 	// Add color scheme setting and control.
 	$wp_customize->add_setting( 'color_scheme', array(
@@ -254,7 +254,7 @@
 add_action( 'customize_controls_enqueue_scripts', 'twentyfifteen_customize_control_js' );
 
 /**
- * Binds JS handlers to make Customizer preview reload changes asynchronously.
+ * Binds JS handlers to make the Customizer preview reload changes asynchronously.
  *
  * @since Twenty Fifteen 1.0
  */
@@ -266,6 +266,9 @@
 /**
  * Output an Underscore template for generating CSS for the color scheme.
  *
+ * The template generates the css dynamically for instant display in the Customizer preview,
+ * and to be saved in a `theme_mod` for display on the front-end.
+ *
  * @since Twenty Fifteen 1.0
  */
 function twentyfifteen_color_scheme_css_template() {
@@ -512,7 +515,7 @@
 	/* Sidebar Text Color */
 	.site-title a:hover,
 	.site-title a:focus {
-		color: {{ data.sidebar_textcolor2 }};
+		color: {{ data.secondary_sidebar_textcolor }};
 	}
 
 	/* Sidebar Border Color */
@@ -592,7 +595,7 @@
 		.widget blockquote,
 		.widget .wp-caption-text,
 		.widget .gallery-caption {
-			color: {{ data.sidebar_textcolor2 }};
+			color: {{ data.secondary_sidebar_textcolor }};
 		}
 
 		.widget button:hover,
@@ -605,11 +608,11 @@
 		.widget input[type="submit"]:focus,
 		.widget_calendar tbody a:hover,
 		.widget_calendar tbody a:focus {
-			background-color: {{ data.sidebar_textcolor2 }};
+			background-color: {{ data.secondary_sidebar_textcolor }};
 		}
 
 		.widget blockquote {
-			border-color: {{ data.sidebar_textcolor2 }};
+			border-color: {{ data.secondary_sidebar_textcolor }};
 		}
 
 		/* Sidebar Border Color */
Index: src/wp-content/themes/twentyfifteen/js/color-scheme-control.js
===================================================================
--- src/wp-content/themes/twentyfifteen/js/color-scheme-control.js	(revision 30275)
+++ src/wp-content/themes/twentyfifteen/js/color-scheme-control.js	(working copy)
@@ -1,6 +1,7 @@
 /* global colorScheme */
 /**
  * Add a listener to the Color Scheme control to update other color controls to new values/defaults.
+ * Also trigger an update of the Color Scheme CSS when a color is changed.
  */
 
 ( function( api ) {
@@ -45,6 +46,7 @@
 		}
 	} );
 
+	// Generate the CSS for the current Color Scheme.
 	function getCSS() {
 		var scheme = api( 'color_scheme' )(),
 			colors = _.object( colorSchemeKeys, colorScheme[ scheme ].colors );
@@ -58,7 +60,7 @@
 		colors['secondary_textcolor'] = Color( colors.textcolor ).toCSS( 'rgba', 0.7 );
 		colors['border_color'] = Color( colors.textcolor ).toCSS( 'rgba', 0.1 );
 		colors['border_focus_color'] = Color( colors.textcolor ).toCSS( 'rgba', 0.3 );
-		colors['sidebar_textcolor2'] = Color( colors.sidebar_textcolor ).toCSS( 'rgba', 0.7 );
+		colors['secondary_sidebar_textcolor'] = Color( colors.sidebar_textcolor ).toCSS( 'rgba', 0.7 );
 		colors['sidebar_border_color'] = Color( colors.sidebar_textcolor ).toCSS( 'rgba', 0.1 );
 		colors['sidebar_border_focus_color'] = Color( colors.sidebar_textcolor ).toCSS( 'rgba', 0.3 );
 
Index: src/wp-content/themes/twentyfifteen/js/customize-preview.js
===================================================================
--- src/wp-content/themes/twentyfifteen/js/customize-preview.js	(revision 30275)
+++ src/wp-content/themes/twentyfifteen/js/customize-preview.js	(working copy)
@@ -10,7 +10,7 @@
 		                    .find( '#twentyfifteen-color-scheme-css' );
 	}
 
-	// Site title and description.
+	// Site title.
 	wp.customize( 'blogname', function( value ) {
 		value.bind( function( to ) {
 			$( '.site-title a' ).text( to );
@@ -17,12 +17,14 @@
 		} );
 	} );
 
+	// Site tagline.
 	wp.customize( 'blogdescription', function( value ) {
 		value.bind( function( to ) {
 			$( '.site-description' ).text( to );
 		} );
 	} );
-	
+
+	// Color Scheme CSS.
 	wp.customize( 'color_scheme_css', function( value ) {
 		value.bind( function( to ) {
 			$style.html( to );