[Klaus]

Well, the charts are actually easy to read.
You may notice that there are 5 vertical segments.
Top to bottom:
- Excellent
- Very good
- good
- fair
- poor
And there are 3-4 bars per aperture representing the center to corner performance.

Of course, the final rating reflects that but there's no magic in there really.

As far as legacy lenses are concerned - there are very few. The interest in those lenses is just very low.