Comment 2 for bug 2051256

Looking at those lines it indeed seems coming from pythia8 handling of MLM code (from S. Prestel):
https://github.com/mg5amcnlo/MG5aMC_PY8_interface/blob/a7b38a861a765a720e35311af0c83bb87bbd980a/MG5aMC_PY8_interface.cc#L707

Now the first question is why such flag are included in the hepmc...
They are certainly needed at the lhef level but not sure why Stephan include those in the hepmc.

More important question (but related) is which code are going to break if we change them.
The most likely issue would come from CMSSW. Will contact them to check...

Cheers,

Olivier