I suspect they have done no work at all. If they had found a message they would say so, otherwise they are speculating or seeking grant money.
There seems to be alot of "science" lately that will come out and proclaim something like "Evidence shows that if it gets warmer, more ice will melt"
Making eye catching headlines must be the new metric for excellence.
And a posit like this article suggests is unprovable. Seemingly intelligent structure occurs all over the place.