Your bookmarks are stored in our server in encrypted form (Mozilla can't read it).

They are on Sync servers by Mozilla. from https://support.mozilla.org/en-US/kb/how-firefox-securely-saves-passwords Firefox Sync ensures that your data is encrypted before it ever leaves your device, and that the password to unlock this encryption is never transmitted to the server. This is done by applying some cryptographic hashing to your Firefox Account password to strengthen it when you enter it, and deriving the authentication and encryption keys. https://support.mozilla.org/en-US/kb/how-firefox-securely-saves-passwords