The Java Cryptography Extension enables applications to use stronger versions of standard algorithms.
JDK 9 and later ship with, and use by default, the unlimited policy files.
The unlimited policy files for earlier releases available here are required only for JDK 8, 7, and 6 updates earlier than 8u161, 7u171, and 6u16. On those versions and later the policy files are included, but not enabled by default.
See JDK-8170157 for details.