It's a thin piece of card paper about 2 inches by 6 inches. It's compatible with most platforms. Yeah it has folds and creases from heavy use too and provides full access to where ever you've left off before the cat puked, the dog shit himself, and the kid started coloring on the wall. 😉
Discussion
Sorry couldn't not do that.
Depending upon your definition of sync, the self hosted password managers can usually handle files and such. Just drop backups of your browser bookmarks into your password manager that is cross platform capable. Or instead of bookmark backup files use simple text files?