Oracle-less options are a primitive ERC-20 token that has the functionality of a vanilla American option. They are physically settled, which means there doesn't need to be price oracles to determine settlement values. Collateral is held by the option tokens, and the collateral is sold when the options are exercised. This documentation explains the specification for the Option.sol and Redeem.sol contracts.
The option tokens are deployed using proxies, which delegatecall to the following implementation contracts:
The source code is available on github: Primitive V1 Options Source. The code is open-sourced under the MIT license.
This is a low-level contract which should NEVER be directly called by an externally owned account. Only a smart contract which has implemented the correct checks can safely call into this option contract.
This is the contract which has the implemented functionality to be a vanilla option.