An ethPM registry is an on-chain datastore for package releases. For each package release, three pieces of information are committed to storage:
a package name
a package version
the content-addressed URI associated with the package's manifest.
ERC1319 was written to define the API for an on-chain ethPM registry. It is the minimum feasible API for a registry to interoperate with various ethPM tooling. It is encouraged for people to build their own registry implementations that extend upon the standard to support any kind of specialized behavior.
There are a couple different implementations of ERC1319 available.
Solidity implementation with release deletion (but prevents re-releasing the same package version)
Solidity implementation without release deletion
ethPM-CLI provides a simple command deploy the Simple Registry to any blockchain.
Escape-Truffle provides this script to assist with deploying its series of smart contracts.