In fact, at the tip of the 2.7 branch in `sysmodule.c` we have:

static PyStructSequence_Field windows_version_fields[] = {
    {"major", "Major version number"},
    {"minor", "Minor version number"},
    {"build", "Build number"},
    {"platform", "Operating system platform"},
    {"service_pack", "Latest Service Pack installed on the system"},
    {"service_pack_major", "Service Pack major version number"},
    {"service_pack_minor", "Service Pack minor version number"},
    {"suite_mask", "Bit mask identifying available product suites"},
    {"product_type", "System product type"},
    {0}
};

https://hg.python.org/cpython/file/2.7/Python/sysmodule.c