Format for Party hand histories

[KJ o]

I just noticed that the format for hand histories that are e-mailed from Party are different from those stored locally. This leads to a bunch of questions:

Is there a good reason for this?

Has this always been the case?

Is one method expected to be more stable over time?

I'm writing a simple flex/bison parser for my own use, and would only like to spend time on the "best" format.