Cryptomator 2.0 for iOS: Open Source and Beta Release

The encrypted masterkey file is stored in the cloud: Why is the masterkey stored in the cloud?

Means, even if someone would have access to the cloud AND has the password, decryption is impossible?

No, if someone has access to the cloud and has the password, decryption is possible. That’s basically the “normal” use case for using Cryptomator on multiple devices.