In the full spec document, there are hints that, if the top contenders either meet/exceed all the specs, or miss all the same, they will judge based on related quantities.
Explicitly, the condition is, if none meet EMC -- but perhaps they will apply the same reasoning to other constraints, assuming no one achieves them (or everyone does).
In the full spec document, they specify loads and weighing by CEC.
In particular, you aren't going to do more than 30W by convection and radiation alone, and no more than 100W (= 95%) with forced air.
It's referred to as a power resistor. Presumably, they have a good bench supply of some sort (presumably, better than 1% voltage tolerance), and a bigass wirewound (which might not have as good a tolerance -- something to keep in mind).
No one makes them in high enough voltage (EPC's stop at 200V). The other companies that claim products in that voltage range, don't have any product available (sometimes not even the preliminary datasheets).
Likewise, no one makes SiC with low enough Rds(ON). This is a silicon project, through and through -- which is kind of silly given the interested parties.
If they had specified a lower voltage input, GaN would be actually available. But so would a smorgasboard of Si.
If they had specified a higher voltage input, SiC would be attractive -- but Si still competitive, and GaN completely out. And also such a high voltage (indeed, "medium voltage" by power line standards!) is... kind of unreasonable in the first place.
Tim