Board Thread:Support Requests - Getting Technical/@comment-33878615-20160910201000/@comment-27345308-20160910201415

Modifying "On the Wiki" tab is done through CSS and JavaScript, however, before modifying it sitewidely I'd advise you to contact Staff so you don't violate the customization policy while modifying it.

If you enabled the Forum extension on the wiki, the link should already exist, it's weird that you don't see it. What wiki are you trying to add it on?