diff --git a/.phpcs.xml.dist b/.phpcs.xml.dist
index c71ab7fe143..6209556d799 100644
--- a/.phpcs.xml.dist
+++ b/.phpcs.xml.dist
@@ -227,6 +227,12 @@
 		<exclude-pattern>/inc/wpseo-functions-deprecated\.php$</exclude-pattern>
 	</rule>
 
+	<!-- Ignore unused variables in deprecated functionality. -->
+	<rule ref="VariableAnalysis.CodeAnalysis.VariableAnalysis.UnusedVariable">
+		<exclude-pattern>/src/deprecated/*</exclude-pattern>
+		<exclude-pattern>/inc/wpseo-functions-deprecated\.php$</exclude-pattern>
+	</rule>
+
 	<!-- Exclude deprecated code from select sniffs regarding naming conventions.
 		 These classes are still available to prevent BC-breaks and renaming them would
 		 create a BC-break. -->
diff --git a/admin/class-customizer.php b/admin/class-customizer.php
deleted file mode 100644
index bc6b9e8c7c1..00000000000
--- a/admin/class-customizer.php
+++ /dev/null
@@ -1,249 +0,0 @@
-<?php
-/**
- * WPSEO plugin file.
- *
- * @package WPSEO\Admin\Customizer
- */
-
-/**
- * Class with functionality to support WP SEO settings in WordPress Customizer.
- */
-class WPSEO_Customizer {
-
-	/**
-	 * Holds the customize manager.
-	 *
-	 * @var WP_Customize_Manager
-	 */
-	protected $wp_customize;
-
-	/**
-	 * Template for the setting IDs used for the customizer.
-	 *
-	 * @var string
-	 */
-	private $setting_template = 'wpseo_titles[%s]';
-
-	/**
-	 * Default arguments for the breadcrumbs customizer settings object.
-	 *
-	 * @var array
-	 */
-	private $default_setting_args = [
-		'default'   => '',
-		'type'      => 'option',
-		'transport' => 'refresh',
-	];
-
-	/**
-	 * Default arguments for the breadcrumbs customizer control object.
-	 *
-	 * @var array
-	 */
-	private $default_control_args = [
-		'label'    => '',
-		'type'     => 'text',
-		'section'  => 'wpseo_breadcrumbs_customizer_section',
-		'settings' => '',
-		'context'  => '',
-	];
-
-	/**
-	 * Construct Method.
-	 */
-	public function __construct() {
-		add_action( 'customize_register', [ $this, 'wpseo_customize_register' ] );
-	}
-
-	/**
-	 * Function to support WordPress Customizer.
-	 *
-	 * @param WP_Customize_Manager $wp_customize Manager class instance.
-	 *
-	 * @return void
-	 */
-	public function wpseo_customize_register( $wp_customize ) {
-		if ( ! WPSEO_Capability_Utils::current_user_can( 'wpseo_manage_options' ) ) {
-			return;
-		}
-
-		$this->wp_customize = $wp_customize;
-
-		$this->breadcrumbs_section();
-		$this->breadcrumbs_blog_show_setting();
-		$this->breadcrumbs_separator_setting();
-		$this->breadcrumbs_home_setting();
-		$this->breadcrumbs_prefix_setting();
-		$this->breadcrumbs_archiveprefix_setting();
-		$this->breadcrumbs_searchprefix_setting();
-		$this->breadcrumbs_404_setting();
-	}
-
-	/**
-	 * Add the breadcrumbs section to the customizer.
-	 *
-	 * @return void
-	 */
-	private function breadcrumbs_section() {
-		$section_args = [
-			/* translators: %s is the name of the plugin */
-			'title'           => sprintf( __( '%s Breadcrumbs', 'wordpress-seo' ), 'Yoast SEO' ),
-			'priority'        => 999,
-			'active_callback' => [ $this, 'breadcrumbs_active_callback' ],
-		];
-
-		$this->wp_customize->add_section( 'wpseo_breadcrumbs_customizer_section', $section_args );
-	}
-
-	/**
-	 * Returns whether or not the breadcrumbs are active.
-	 *
-	 * @return bool
-	 */
-	public function breadcrumbs_active_callback() {
-		return current_theme_supports( 'yoast-seo-breadcrumbs' ) || WPSEO_Options::get( 'breadcrumbs-enable' );
-	}
-
-	/**
-	 * Adds the breadcrumbs show blog checkbox.
-	 *
-	 * @return void
-	 */
-	private function breadcrumbs_blog_show_setting() {
-		$index        = 'breadcrumbs-display-blog-page';
-		$control_args = [
-			'label'           => __( 'Show blog page in breadcrumbs', 'wordpress-seo' ),
-			'type'            => 'checkbox',
-			'active_callback' => [ $this, 'breadcrumbs_blog_show_active_cb' ],
-		];
-
-		$this->add_setting_and_control( $index, $control_args );
-	}
-
-	/**
-	 * Returns whether or not to show the breadcrumbs blog show option.
-	 *
-	 * @return bool
-	 */
-	public function breadcrumbs_blog_show_active_cb() {
-		return get_option( 'show_on_front' ) === 'page';
-	}
-
-	/**
-	 * Adds the breadcrumbs separator text field.
-	 *
-	 * @return void
-	 */
-	private function breadcrumbs_separator_setting() {
-		$index        = 'breadcrumbs-sep';
-		$control_args = [
-			'label' => __( 'Breadcrumbs separator:', 'wordpress-seo' ),
-		];
-		$id           = 'wpseo-breadcrumbs-separator';
-
-		$this->add_setting_and_control( $index, $control_args, $id );
-	}
-
-	/**
-	 * Adds the breadcrumbs home anchor text field.
-	 *
-	 * @return void
-	 */
-	private function breadcrumbs_home_setting() {
-		$index        = 'breadcrumbs-home';
-		$control_args = [
-			'label' => __( 'Anchor text for the homepage:', 'wordpress-seo' ),
-		];
-
-		$this->add_setting_and_control( $index, $control_args );
-	}
-
-	/**
-	 * Adds the breadcrumbs prefix text field.
-	 *
-	 * @return void
-	 */
-	private function breadcrumbs_prefix_setting() {
-		$index        = 'breadcrumbs-prefix';
-		$control_args = [
-			'label' => __( 'Prefix for breadcrumbs:', 'wordpress-seo' ),
-		];
-
-		$this->add_setting_and_control( $index, $control_args );
-	}
-
-	/**
-	 * Adds the breadcrumbs archive prefix text field.
-	 *
-	 * @return void
-	 */
-	private function breadcrumbs_archiveprefix_setting() {
-		$index        = 'breadcrumbs-archiveprefix';
-		$control_args = [
-			'label' => __( 'Prefix for archive pages:', 'wordpress-seo' ),
-		];
-
-		$this->add_setting_and_control( $index, $control_args );
-	}
-
-	/**
-	 * Adds the breadcrumbs search prefix text field.
-	 *
-	 * @return void
-	 */
-	private function breadcrumbs_searchprefix_setting() {
-		$index        = 'breadcrumbs-searchprefix';
-		$control_args = [
-			'label' => __( 'Prefix for search result pages:', 'wordpress-seo' ),
-		];
-
-		$this->add_setting_and_control( $index, $control_args );
-	}
-
-	/**
-	 * Adds the breadcrumb 404 prefix text field.
-	 *
-	 * @return void
-	 */
-	private function breadcrumbs_404_setting() {
-		$index        = 'breadcrumbs-404crumb';
-		$control_args = [
-			'label' => __( 'Breadcrumb for 404 pages:', 'wordpress-seo' ),
-		];
-
-		$this->add_setting_and_control( $index, $control_args );
-	}
-
-	/**
-	 * Adds the customizer setting and control.
-	 *
-	 * @param string      $index           Array key index to use for the customizer setting.
-	 * @param array       $control_args    Customizer control object arguments.
-	 *                                     Only those different from the default need to be passed.
-	 * @param string|null $id              Optional. Customizer control object ID.
-	 *                                     Will default to 'wpseo-' . $index.
-	 * @param array       $custom_settings Optional. Customizer setting arguments.
-	 *                                     Only those different from the default need to be passed.
-	 *
-	 * @return void
-	 */
-	private function add_setting_and_control( $index, $control_args, $id = null, $custom_settings = [] ) {
-		$setting                  = sprintf( $this->setting_template, $index );
-		$control_args             = array_merge( $this->default_control_args, $control_args );
-		$control_args['settings'] = $setting;
-
-		$settings_args = $this->default_setting_args;
-		if ( ! empty( $custom_settings ) ) {
-			$settings_args = array_merge( $settings_args, $custom_settings );
-		}
-
-		if ( ! isset( $id ) ) {
-			$id = 'wpseo-' . $index;
-		}
-
-		$this->wp_customize->add_setting( $setting, $settings_args );
-
-		$control = new WP_Customize_Control( $this->wp_customize, $id, $control_args );
-		$this->wp_customize->add_control( $control );
-	}
-}
diff --git a/composer.json b/composer.json
index 5bad5b6086a..cc188b0e052 100644
--- a/composer.json
+++ b/composer.json
@@ -92,8 +92,8 @@
 			"Yoast\\WP\\SEO\\Composer\\Actions::check_coding_standards"
 		],
 		"check-cs-thresholds": [
-			"@putenv YOASTCS_THRESHOLD_ERRORS=2549",
-			"@putenv YOASTCS_THRESHOLD_WARNINGS=267",
+			"@putenv YOASTCS_THRESHOLD_ERRORS=2545",
+			"@putenv YOASTCS_THRESHOLD_WARNINGS=253",
 			"Yoast\\WP\\SEO\\Composer\\Actions::check_cs_thresholds"
 		],
 		"check-cs": [
diff --git a/src/deprecated/admin/class-customizer.php b/src/deprecated/admin/class-customizer.php
new file mode 100644
index 00000000000..57b68c317ac
--- /dev/null
+++ b/src/deprecated/admin/class-customizer.php
@@ -0,0 +1,72 @@
+<?php
+/**
+ * WPSEO plugin file.
+ *
+ * @package WPSEO\Admin\Customizer
+ */
+
+/**
+ * Class with functionality to support WP SEO settings in WordPress Customizer.
+ *
+ * @codeCoverageIgnore
+ * @deprecated 22.8
+ */
+class WPSEO_Customizer {
+
+	/**
+	 * Holds the customize manager.
+	 *
+	 * @deprecated 22.8
+	 *
+	 * @var WP_Customize_Manager
+	 */
+	protected $wp_customize;
+
+	/**
+	 * Construct Method.
+	 *
+	 * @codeCoverageIgnore
+	 * @deprecated 22.8
+	 */
+	public function __construct() {
+		_deprecated_function( __METHOD__, 'Yoast SEO 22.8' );
+	}
+
+	/**
+	 * Function to support WordPress Customizer.
+	 *
+	 * @param WP_Customize_Manager $wp_customize Manager class instance.
+	 *
+	 * @codeCoverageIgnore
+	 * @deprecated 22.8
+	 *
+	 * @return void
+	 */
+	public function wpseo_customize_register( $wp_customize ) {
+		_deprecated_function( __METHOD__, 'Yoast SEO 22.8' );
+	}
+
+	/**
+	 * Returns whether or not the breadcrumbs are active.
+	 *
+	 * @codeCoverageIgnore
+	 * @deprecated 22.8
+	 *
+	 * @return void
+	 */
+	public function breadcrumbs_active_callback() {
+		_deprecated_function( __METHOD__, 'Yoast SEO 22.8' );
+	}
+
+	/**
+	 * Returns whether or not to show the breadcrumbs blog show option.
+	 *
+	 * @codeCoverageIgnore
+	 * @deprecated 22.8
+	 *
+	 * @return void
+	 */
+	public function breadcrumbs_blog_show_active_cb() {
+		_deprecated_function( __METHOD__, 'Yoast SEO 22.8' );
+	}
+}
diff --git a/wp-seo-main.php b/wp-seo-main.php
index aa560212d2a..bc1cbd2a469 100644
--- a/wp-seo-main.php
+++ b/wp-seo-main.php
@@ -363,9 +363,6 @@ function wpseo_init() {
 		require_once WPSEO_PATH . 'inc/wpseo-non-ajax-functions.php';
 	}
 
-	// Init it here because the filter must be present on the frontend as well or it won't work in the customizer.
-	new WPSEO_Customizer();
-
 	$integrations   = [];
 	$integrations[] = new WPSEO_Slug_Change_Watcher();