Default: true [Since 6.5.5]
It specifies whether to show ZK version in each page.
By default, each page will display the comment contains ZK version which the current web application is using. If a user wants to hide the info in security consideration, he can specify this library property to false.
The value other than "true" is considered as false. And this value will be taken as salt to obfuscate the version info which is needed in resource caching. For instance, "zk_is_good" can be used to hide the version info and obfuscate it when needed.