Pep command cannot fetch PEP 0.

[Numerlor]

The PEP 0 is an index of all the other PEPs;
instead of being in the github repo directly, it's generated automatically through a script present there.
If implemented, scraping the site for it seems to be the better option as generating it would require the whole up to date repo.
The header is a constant in the pep0 package and can be gotten from there in case of future changes
or as suggested in the comment below https://github.com/python/peps/blob/master/pep0/constants.py#L10-L20

[Numerlor]

Or looking at the current output of pep, it could be hardcoded as it'll always be active and the other things are static