The word-break class is used to break up words that are too long to render without overflowing. This is used for instance when viewing a full record.
It was committed in 2014 and reads:
as is discussed in this blog post the above class is a widely used solution but however it doesn't render hyphens in Firefox and Opera mini (and I've been told Safari but I've not confirmed).
the aforementioned blog post suggests this fix:
which I have confirmed works in Chrome, Firefox and Opera.
The attached screenshots shows rendering in Firefox in current version (without-hyphens-png) and then rendering using the new class (with-hyphens.png).