Answering my own post ...
Got this reply from Arturia, if anyone is interested:
"User presets are stored in "labo2.db"."
On OS X, this file can be found ~/Library/Arturia/Analog Lab.
You should make sure to back up this file, so you don't lose your user patches.
As a future feature request, I would like to see Arturia implement something more user friendly, like the ability to choose a folder to store User Presets during the Save dialog. Or menu commands: Export User Presets/Import Presets, or something ...