Minify HTML Page Output - Can be toggled within the Control Panel[UPDATE]
Update Smarty from version 2.6 to 3.1[FIX]
Viewing Subscriptions in CP would display a blank header and sidebar.Minify HTML Page Output
When this feature is enabled, it will remove all unnecessary characters from a page's html without changing its functionality. The process removes unnecessary characters which usually include white space characters, new line characters, and comments, which are used to add readability to the code but are not required for it to execute. Because minification reduces the size of code, minified code requires less data to be transferred. As a result, it loads faster, helping to decrease page load times.
Further reading at:https://en.wikipedia.org/wiki/Minification_(programming)