I am guessing replacement worldclock uses QSettings whereas the old one didn't.
I would think /home/user/.clock/wdb-user is the settings.
Sorry to disappoint, but it seems to be database of 396 cities for the world map, with geographic coordinates included. Though I wouldn't recommend using this file, unless it's proven to be open-source-licensed.
Is there any chance of adding an option to remove the "alarm flag" from an alarm. I [don't like/have got used to] not seeing the alarm status symbol for my regular day to day alarms. This means I have to use alarmd for these tasks when I could use worldclock.