Exp: experimental code to an unstable core version, community involvement likely, not to be deployed in production

Dev: code stabilized to a stable (or almost stable) core version, can be used in development projects, production deployment needs pro support

Production: production-level version. Features no longer change between minor versions. This is usually the one you will want to deploy.

Limited: limited support. Code is no longer actively maintained, but can still be used in production until the site is updated to a next version.