Where is --start-value-enumeration option coming from?

What is this option exactly and how/why does it get inserted in a workflow ?

Trying something like :

o2-mch-digits-reader-workflow --infile digits_ref.data -b |  o2-mch-entropy-encoder-workflow -b | o2-ctf-writer-workflow --onlyDet MCH --help ctf-writer

I get this option (and siblings) appear in the help while AFAIK none of the three devices explicitly define them :

[INFO] Mapping of global channel and (PM, PM channel) pair
[INFO] Detectors list:
ALICE O2 DPL workflow driver (ctf-writer help)

Data processor options: ctf-writer:
  --save-dict-after arg (=-1)          In dictionary generation mode save it
                                       dictionary after certain number of TFs
  --start-value-enumeration arg (=0)   initial value for the enumeration
  --end-value-enumeration arg (=-1)    final value for the enumeration
  --step-value-enumeration arg (=1)    step between one value and the other