Also confused about why this was closed.

This format is still frequently used. In the absence of a solution in the standard library, I'm using this kludge to strip the leading `#HttpOnly_`.


    from tempfile import NamedTemporaryFile
    from http.cookiejar import MozillaCookieJar
    from contextlib import contextmanager

    def fix_cookie_jar_file(orig_cookiejarfile):
        with NamedTemporaryFile(mode='w+') as cjf:
            with open(orig_cookiejarfile, 'r') as ocf:
            for l in ocf:            
                cjf.write(l[10:] if l.startswith('#HttpOnly_') else l)
            cjf.seek(0)
        yield cjf.name

    MozillaCookieJar(filename=fix_cookie_jar_file(orig_cookiejarfile))