needed for backwards compatibility (WP < 5.1).
				'span'     => array(
					'aria-hidden' => true,
				),
				'input'    => array(
					'aria-describedby' => true,
				),
				'select'   => array(
					'aria-describedby' => true,
				),
				'textarea' => array(
					'aria-describedby' => true,
				),
			);

			// Add the global allowed attributes to each html element.
			$a11y_tags = array_map( '_wp_add_global_attributes', $a11y_tags );
		}

		return array_merge_recursive( $allowed_post_tags, $a11y_tags );
	}

	/**
	 * Extends the allowed post tags with input, select and option tags.
	 *
	 * @param array $allowed_post_tags The allowed post tags.
	 * @codeCoverageIgnore
	 *
	 * @return array The allowed tags including post tags, input tags, select tags and option tags.
	 */
	public static function extend_kses_post_with_forms( $allowed_post_tags ) {
		static $input_tags;

		if ( isset( $input_tags ) === false ) {
			$input_tags = array(
				'input' => array(
					'accept'          => true,
					'accesskey'       => true,
					'align'           => true,
					'alt'             => true,
					'autocomplete'    => true,
					'autofocus'       => true,
					'checked'         => true,
					'contenteditable' => true,
					'dirname'         => true,
					'disabled'        => true,
					'draggable'       => true,
					'dropzone'        => true,
					'form'            => true,
					'formaction'      => true,
					'formenctype'     => true,
					'formmethod'      => true,
					'formnovalidate'  => true,
					'formtarget'      => true,
					'height'          => true,
					'hidden'          => true,
					'lang'            => true,
					'list'            => true,
					'max'             => true,
					'maxlength'       => true,
					'min'             => true,
					'multiple'        => true,
					'name'            => true,
					'pattern'         => true,
					'placeholder'     => true,
					'readonly'        => true,
					'required'        => true,
					'size'            => true,
					'spellcheck'      => true,
					'src'             => true,
					'step'            => true,
					'tabindex'        => true,
					'translate'       => true,
					'type'            => true,
					'value'           => true,
					'width'           => true,

					/*
					 * Below are attributes that are needed for backwards compatibility (WP < 5.1).
					 * They are used for the social media image in the metabox.
					 * These can be removed once we move to the React versions of the social previews.
					 */
					'data-target'     => true,
					'data-target-id'  => true,
				),
				'select' => array(
					'accesskey'       => true,
					'autofocus'       => true,
					'contenteditable' => true,
					'disabled'        => true,
					'draggable'       => true,
					'dropzone'        => true,
					'form'            => true,
					'hidden'          => true,
					'lang'            => true,
					'multiple'        => true,
					'name'            => true,
					'onblur'          => true,
					'onchange'        => true,
					'oncontextmenu'   => true,
					'onfocus'         => true,
					'oninput'         => true,
					'oninvalid'       => true,
					'onreset'         => true,
					'onsearch'        => true,
					'onselect'        => true,
					'onsubmit'        => true,
					'required'        => true,
					'size'            => true,
					'spellcheck'      => true,
					'tabindex'        => true,
					'translate'       => true,
				),
				'option' => array(
					'class'    => true,
					'disabled' => true,
					'id'       => true,
					'label'    => true,
					'selected' => true,
					'value'    => true,
				),
			);

			// Add the global allowed attributes to each html element.
			$input_tags = array_map( '_wp_add_global_attributes', $input_tags );
		}

		return array_merge_recursive( $allowed_post_tags, $input_tags );
	}

	/**
	 * Gets an array of enabled features.
	 *
	 * @return string[] The array of enabled features.
	 */
	public static function retrieve_enabled_features() {
		$enabled_features = array();
		if ( defined( 'YOAST_SEO_ENABLED_FEATURES' ) ) {
			$enabled_features = preg_split( '/,\W*/', YOAST_SEO_ENABLED_FEATURES );
		}
		// Make the array of enabled features filterable, so features can be enabled at will.
		$enabled_features = apply_filters( 'wpseo_enable_feature', $enabled_features );

		return $enabled_features;
	}

	/* ********************* DEPRECATED METHODS ********************* */

	/**
	 * Returns the language part of a given locale, defaults to english when the $locale is empty.
	 *
	 * @see WPSEO_Language_Utils::get_language()
	 *
	 * @deprecated 9.5
	 * @codeCoverageIgnore
	 *
	 * @param string $locale The locale to get the language of.
	 *
	 * @return string The language part of the locale.
	 */
	public static function get_language( $locale ) {
		_deprecated_function( __METHOD__, 'WPSEO 9.5', 'WPSEO_Language_Utils::get_language' );
		return WPSEO_Language_Utils::get_language( $locale );
	}

	/**
	 * Returns the user locale for the language to be used in the admin.
	 *
	 * WordPress 4.7 introduced the ability for users to specify an Admin language
	 * different from the language used on the front end. This checks if the feature
	 * is available and returns the user's language, with a fallback to the site's language.
	 * Can be removed when support for WordPress 4.6 will be dropped, in favor
	 * of WordPress get_user_locale() that already fallbacks to the site's locale.
	 *
	 * @see WPSEO_Language_Utils::get_user_locale()
	 *
	 * @deprecated 9.5
	 * @codeCoverageIgnore
	 *
	 * @return string The locale.
	 */
	public static function get_user_locale() {
		_deprecated_function( __METHOD__, 'WPSEO 9.5', 'WPSEO_Language_Utils::get_user_locale' );

		return WPSEO_Language_Utils::get_user_locale();
	}
}