It's a free open source app that runs on your local machine and stores your passwords locally - never uploads your passwords to a server. But it does this securely.
And you can run it on multiple machines (and phones) and transfer the passwords (the vault) without ever uploading anything to servers.
If you like to have synced database between devices with minimal risk of exposure I would recommend setting it up to use a master password AND generated key file. I do this, then sync my database to cloud/butt and just keep my key file offline and on device only.
Edit: I believe you can also use a FIDO/U2F key (yubikey, google titan, etc.) in place of a key file but 2 password lock is great even if someone guesses your master password, the database is still useless without the 2nd key.
Obviously it's not as nice as having a cloud service, but it's open-source and doesn't require trusting a third party, which I like.