The program relies on pulling the bookmarks out of the filesystem. I have no idea how feasible it would be on Android given the sandboxed nature of apps.
However, it is possible to manually export from time to time your bookmarks to a folder that is synced with Syncthing for example. Gosuki has a bookmark html auto import feature that watches a folder and imports all bookmarks files when a change is detected. This is how I am personally doing it right now.
Yes that's exactly how it works. It's the most difficult part of the project especially for Mozilla browsers.
I figured this is the last place browser vendors didn't dare yet to lock us out from it.