That's easy, they'll check whether there's one big fingerprint vs >10^10 little tiny fingerprints and conclude accordingly \j

> Researchers also found that such a world could survive its passage through the Sun's outer layers while losing very little mass, which suggests that planets may leave detectable fingerprints inside their host stars long after they have disappeared.

So I guess the large size would have permitted it to smuggle stuff into the core that would have just vaporised in the corona if carried by many smaller objects?

This, but how do they rule out the extra stuff landing in the sun much earlier - when the solar system was still a pre-solar nebula, and which bits would end up where (sun vs. planets vs. whatever) was far from settled?

>But it seems unclear to me how the researchers would distinguish between one super-Earth and >10^10 smaller rocks?

I have a similar feeling when life on earth is suggested to be "alien", arriving via debris in the solar system as the earth formed. Isn't everything in the solar system coalesced from the same debris?