Thinking through the practicalities of an "H10" engine.
Flat-ten which is what I think this is, would be incredibly balanced (as all boxers are) but would have to climb around the issues of crank whip.
An H engine like the H16 in BRM P83 grand prix car, would be technically impossible, owing to the configuration needed (namely 10 doesn't divide into four banks of cylinders); which is why this is probably a boxer; in the same way that Subaru market their engines as H4 and H6. Then I found out that Chevrolet actually did produce a flat-ten as a prototype Corvair.
This is going to be a challenge for the manufacturers as they wrestle with the FART. Everyone is one the same page, having never built that engine before.
(Also, I want some of the good Doctor's Magic Eye Solution. Pain once every three weeks sounds like a good tradeoff.)