Manual:$wgAjaxWatch

Details
Enable watching/unwatching pages using Ajax.

Requires   and   to be true too.

Causes wfAjaxWatch to be added to  .

In MediaWiki 1.27, $wgAjaxWatch has been removed. The functionality is now always enabled.

Other
If you want to add a Watch/Unwatch tab (the tab with the star), set   to true.