It's a public testnet with most of the functionality.

The initial testnet release is a self-contained network which allows external developers to build their first secret contracts. This developer release provides a deployable Docker network that holds a simplified, containerized environment that also makes available multiple core components of the Enigma protocol. Developers are able to deploy secret contracts, and verify that these contracts are executed as intended.
Secret contracts operate by being executed in a retrofitted EVM running inside a Trusted Execution Environment (TEE), based on Intel’s SGX technology. This supports out-of-the-box interoperability with Solidity, as well as the Ethereum network.

More info at https://twitter.com/enigmampc and https://blog.enigma.co/@EnigmaMPC