Context from https://bugs.chromium.org/p/chromium/issues/detail?id=811976#c37:

> First, Mac Retina bots are actually running 10.12 instead of 10.11 despite what their names suggest (issue 818524).
But the command we use to detect Retina doesn't work on 10.12, so these bots don't consider themselves Retina ( issue 818558 ).
> As a result, mac-retina baselines aren't in use now at all.
> The mismatch you are seeing is because the expected results on the Retina bot are actually mac{-mac10.12}/ baselines.
> Lastly, the Mac Retina bot on the waterfall has been disconnected somehow for a month so we haven't noticed...

So: 
 

Context from https://bugs.chromium.org/p/chromium/issues/detail?id=811976#c37:

> First, Mac Retina bots are actually running 10.12 instead of 10.11 despite what their names suggest (issue 818524).
But the command we use to detect Retina doesn't work on 10.12, so these bots don't consider themselves Retina ( issue 818558 ).
> As a result, mac-retina baselines aren't in use now at all.
> The mismatch you are seeing is because the expected results on the Retina bot are actually mac{-mac10.12}/ baselines.
> Lastly, the Mac Retina bot on the waterfall has been disconnected somehow for a month so we haven't noticed...