While reviewing the download support patch ap raised the issue that we have structs with names starting with underscore. While there is apparently no practical issue, he believes this to be wrong, and I suggested we should look at naming the pre-typedef structures in a better way.
We have never been able to address this and it turns out there are a lot more of these on the code now, including on cocoa, cf and ios port code. I don't think we will be addressing this.