MySQL 8.0 Release Notes
MySQL 8.0 Source Code Documentation
Other storage engines may be available from third parties and community members that have used the Custom Storage Engine interface.
Third party engines are not supported by MySQL. For further information, documentation, installation guides, bug reporting or for any help or assistance with these engines, please contact the developer of the engine directly.
For more information on developing a customer storage engine that can be used with the Pluggable Storage Engine Architecture, see MySQL Internals: Writing a Custom Storage Engine.