packages/kirki-framework/core/src/Settings.php
final private function add_setting( $classname, $setting, $default, $type, $capability, $transport, $sanitize_callback ) {

		$this->wp_customize->add_setting(
			new $classname(
				$this->wp_customize,
				$setting,
				[
					'default'           => $default,
					'type'              => $type,
					'capability'        => $capability,
					'transport'         => $transport,
					'sanitize_callback' => $sanitize_callback,
				]
			)
		);

	}
final private function add_setting( $classname, $setting, $default, $type, $capability, $transport, $sanitize_callback ) {

		$this->wp_customize->add_setting(
			new $classname(
				$this->wp_customize,
				$setting,
				[
					'default'           => $default,
					'type'              => $type,
					'capability'        => $capability,
					'transport'         => $transport,
					'sanitize_callback' => $sanitize_callback,
				]
			)
		);

	}
final private function add_setting ( $ classname , $ setting , $ default , $ type , $ capability , $ transport , $ sanitize_callback ) { $ this -> wp_customize -> add_setting ( new $ classname ( $ this -> wp_customize , $ setting , [ 'default' => $ default , 'type' => $ type , 'capability' => $ capability , 'transport' => $ transport , 'sanitize_callback' => $ sanitize_callback , ] ) ) ; }
This is where we're finally adding the setting to the Customizer.

@access private
@param string       $classname           The name of the class that will be used to create this setting.
We're getting this from $this->setting_types.
@param string       $setting             The setting-name.
If settings is an array, then this method is called per-setting.
@param string|array $default             Default value for this setting.
@param string       $type                The data type we're using. Valid options: theme_mod|option.
@param string       $capability          @see https://codex.wordpress.org/Roles_and_Capabilities.
@param string       $transport           Use refresh|postMessage.
@param string|array $sanitize_callback   A callable sanitization function or method.
This is where we re finally adding the setting to the Customizer .