The desktop application Cryptomator has been peer-reviewed by the community. Its cryptographic libraries use only cryptographic primitives of well-known open source libraries like JCA, OpenSSL, and Common Crypto. Except SIV Mode, which is the only self-implemented cryptographic primitive.
SIV-Mode has been reviewed by Tim McLean. The report on SIV Mode 1.0.8 can be found here and the issues found have been fixed with version 1.1.0.