If 'char' in-place of 'int' is a legacy quirk, then I get it. I just find it odd that over the course of twenty-five years the required expense couldn't be made to update the data type. It just makes more sense.
If you find it odd you haven't worked on any large projects that have enormous backlogs of bugs and features to build which need to be prioritized. Bugs that will never actually manifest in normal usage should be far down the list of things to fix, particularly if they are in 25 year old code that is battle hardened and in the critical path.