User blog comment:Kirkburn/Technical Update: August 31, 2016/@comment-5288784-20160905130855/@comment-452-20160905144437

I just checked an external wiki which still has the old diffs, and it turns out that the "diffchange diffchange-inline" classes were already applied to whitespace changes in the past.

So anyone who wanted whitespace to be highlighted could have applied CSS to them at any time.