Maybe useful at mmapmodule.c replacing

        /* SVR4 method to map anonymous memory is to open /dev/zero */
        fd = devzero = _Py_open("/dev/zero", O_RDWR);

tagname is unused at UNIX version of new_mmap_object() so if provided something like could be added for Linux only
        fd = memfd_create(tagname, O_RDWR);