Short reminder to myself (because it's not the first time I waste my time googling for the answer):
- Install your own instance of Firefox Sync server (can be: ownCloud Mozilla Sync app, the minimal FSync on a Synology NAS, or the official Mozilla Sync Server)
- If not already done, create a firefox account ().
- Configure your own instance of Sync server to match your firefox account email address. For ownCloud, this is via your profile "Personal" options.
- To configure Firefox Desktop, go to about:config in location bar, and edit "services.sync.tokenServerURI" key to match your server URL.
- To configure Firefox for Android, see the blog post How to connect Firefox for Android to self-hosted Firefox Account and Firefox Sync servers.
- Configure Sync "the normal" way: