That's not really possible with an eu4 mod. Eu4 doesn't allow mods to read or save data. They can only affect your gamestate which doesn't carry over to new campaigns and they can output log messages into game.log (and in a limited way to the error and setup logs), but there is no way to read the log files and they get overwritten automatically anyway. You would need a tool which can either create a custom mod or which can change the privileges in a save file