Don't think so cause these are the names of bowtie2 index files: GCA_000001405.15_GRCh38_no_alt_analysis_set.fna.bowtie_index.1.bt2 GCA_000001405.15_GRCh38_no_alt_analysis_set.fna.bowtie_index.2.bt2 GCA_000001405.15_GRCh38_no_alt_analysis_set.fna.bowtie_index.3.bt2 GCA_000001405.15_GRCh38_no_alt_analysis_set.fna.bowtie_index.4.bt2 GCA_000001405.15_GRCh38_no_alt_analysis_set.fna.bowtie_index.rev.1.bt2 GCA_000001405.15_GRCh38_no_alt_analysis_set.fna.bowtie_index.rev.2.bt2 GCA_000001405.15_GRCh38_no_alt_analysis_set.fna.bowtie_index.tar.gz
They have GRCh38, which means they're human. Besides SAM headers have all human chromossomes 1 to 22, X, Y, Mitochondrial, chrUn and then this chr EBV
Epstein-Barr-Virus decoy sequence. Plenty of information on that available via a simple google search ;-D