Board Thread:Support Requests - Getting Technical/@comment-25908612-20160307205855/@comment-1757994-20160308010401

From mw:Manual:$wgExternalLinkTarget Set a default target for external links. Add the following entry to the  file in order to open links in a new window / tab.

You'd have to ask staff to do it for you.

Or you could write JavaScript to alter the page content to add the attribute to all external  tags.