These don't even exist in Olson any more and they are somewhat problematic because they don't truly correspond to anything else that is real.
SystemV/CST6CDT - CLDR aliases it to CST6CDT. But ICU aliases it to America/Chicago. Neither one of which is truly accurate according to the now commented out rules in Olson.
Since these don't even exist in Olson anymore, I would propose that we just remove these entirely.