If you are about to download it – pause and ask whether you truly need GRCh37. If yes, this decoy version is the correct choice over plain hg19. If not, move to GRCh38.
grep -c "^>" human-g1k-v37-decoy.fasta # Typically ~1200–1300 sequences download human-g1k-v37-decoy.fasta
md5sum human_g1k_v37_decoy.fasta # Expected (verify against original source – may vary by provider) If you are about to download it –