Can anyone here explain why the 18 letter genetic sequence CTCCCTTTGTTGTGTTGT which belongs to chromosome 8 of the human genome appears as a primer and sequencer in WHO'S Covid-19 PCR test?

https://www.who.int/docs/default-source/coronaviruse/whoinhouseassays.pdf?sfvrsn=de3a76aa_2

https://www.ncbi.nlm.nih.gov/nucleotide/NC_000008.11?report=genbank&log$=nuclalign&from=63648346&to=63648363