The "java.vendor.version" system property was introduced by JEP 322 (Time-Based Release Versioning) as a way for a JDK implementor to provide additional version information [1]. Oracle used this property in JDK 10 and 11, but stopped using it as of JDK 12. There is no evidence that any other JDK implementor ever used this property. It no longer serves any useful purpose, so we should remove it.

[1] https://openjdk.java.net/jeps/322#System-properties