On a 3-point arc I'd really like a way to retrieve the Mid Point. The data is visible in the Data Inspector, but there doesn't seem to be a way to retrieve it outside of Python.
The Transformer that I would've expected to help me here would be the ArcPropertyExtractor. As shown below, it contains most of the arc properties, however the Mid Point is not one of them.
The Center property is the center of the circle on which the arc is based, i.e. not the Mid Point halfway on the arc.
Not all arcs are 3-point arcs, so I can imagine giving a calculated value or leaving the attribute empty for non-3-point arcs.