I was reading GDC analysis protocol and stopped on this section
....... In order to increase the accuracy and efficacy of alignment the GDC has added multiple decoy sequences to the GRCh38 reference genome (GCA_000786075.2). Sequences from a variety of viruses were also included to provide information on the presence of oncoviruses.......
Anyone knows where I can find informations about samples containing such traces of viruses ?