User blog comment:Rupert Giles/Layout Changes: Breakpoints and Typography/@comment-4189499-20150520014724/@comment-4189499-20150520033350

The text certainly didn't go up to 16px, which is the main metric I'm using to know that it's not displaying at Desktop XL size.

Just PS, I like this behaviour and think it's right for the screen size, as in the physical screen size.