JDK 10 Early Access Release Notes are available 
JDK 10 Schedule, Status & Features are available 
OpenJDK EA binaries will be available at a later date.
Oracle has proposed: Newer version-string scheme for the Java SE Platform and the JDK
Please see Mark Reinhold's proposal  , feedback via the mailing list to Mark please.
Feedback - If you have suggestions or encounter bugs, please submit them using the usual Java SE bug-reporting channel. Be sure to include complete version information from the output of the java --version command.