Thanks Andrew, and to confirm that it is indeed implemented as a Property.
Kinda expected this since Jun 29. (add area, length properties for hatch entities · qcad/qcad@99a25a2 · GitHub)
I have ‘Always show all properties’ active.
Is the advice then to disable this before installing 3.27.8?
Question: How much faster/slower is InfoAreaCentroid.prototype.getHatchedArea()?
This doesn’t interpolate arc segments, the centroids and their areas methods can handle polylines with bulges.
There will be a minute difference in value and somewhat more pronounced with small radii.
It doesn’t cut the corners off … 
On top, it has a corrected running sum method.
I remarked that calculating the Centroid for John’s example was almost instantaneously.
That does two major things: A) Calculating the hatched area and B) Calculating the centroid position.
Both are pretty demanding with many points, See: center of gravity - #6 by CVH
The main reason why I created it as a Info Tool and never dared to propose it as Properties.
Regards,
CVH