User blog comment:Kirkburn/Technical Update: March 3, 2015/@comment-5558012-20150304153633/@comment-126761-20150304163512

The tooltips are actually part of newer site styleguides - but there hasn't been a lot of appropriate places to implement them so far. They're not using browser tooltips because the info needs to show up immediately, not after a couple of seconds.

I am seeing the issue with wider previews cutting off on the right side - I'll let the team know.