the authors used deep sequencing of environmental DNA (eDNA) to find human genomic information, which they called human genetic bycatch (HGB). This paper was published in Nature Ecology & Evolution. https://www.nature.com/articles/s41559-023-02056-2
This study was also featured in an article in the New York Times.
https://www.nytimes.com/2023/05/15/science/environmental-dna-ethics-privacy.html