Action 'tf_setting_[$setting]_changed_[$namespace]' never called?

[ktmn]

class-titan-framework.php#L731

/**
 * Sets a value in the $setting class variable
 *
 * @since 1.6
 *
 * @param string $setting The name of the setting.
 * @param string $value The value to set.
 *
 * @return void
 */
public function set( $setting, $value ) {
    $oldValue = $this->settings[ $setting ];
    $this->settings[ $setting ] = $value;
    do_action( 'tf_setting_' . $setting . '_changed_' . $this->optionNamespace, $value, $oldValue );
}

Is this function ever called anywhere? I can't seem to find any places, nor can I hook into that action.

I am working with only admin options though, so is it just metabox/customizer related?

Searching for ->set( in the lib directory doesn't yield any results, is there any other syntax this function could be called with?

[ktmn]

Using this one instead: class-option.php#L231