Hier die offizielle Antwort vom Osmand Support Team, welche ich hier auch posten darf.:
Thank you for contacting OsmAnd support team.
Favorites are always synchronized with /sdcard/osmand/favorites.gpx. Share is the export function, and import happens by opening favorites.gpx. Duplicates (favorites with the same name) are not allowed. You can import favorites by just opening the.gpx file from GMail or any file manager. Internally file is always saved to sdcard, but this is very technical level of integration as well.
Now, OsmAnd constantly synchronizes between the favorites.gpx file and the /data/data folder contents in memory - it is always up-to-date. To restore your favorites or transfer them to another phone, you can simply copy the favourites.gpx from the /osmand folder to another phone.
Additionally, the app supports importing GPX from Dropbox and share to any other programs like gmail, dropbox, etc.
If you have any other questions or concerns, please let us know and we will be happy to assist you.
Best Regards,
Damit ist zum Glück alles beantwortet. Danke schön nochmal von mir.