Currently in the JLS, there is a paragraph describing the mapping of the Java SE version vs. the supported Unicode version (https://docs.oracle.com/javase/specs/jls/se15/html/jls-3.html#jls-3.1-110). While Character class is revised each time Unicode is upgraded (thus maintaining the history is fairly effortless), updating JLS each time may increase its maintenance work. Moving this to the Character class description will reduce the JLS maintenance.

Here is the proposed text:
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Character information is based on the Unicode Standard, version 13.0.

The Java platform has supported different versions of the Unicode Standard over time. Upgrades to newer versions of the Unicode Standard occurred in the following Java releases, each indicating the new version:

Java SE 15: Unicode 13.0 / Java SE 13: Unicode 12.1 / Java SE 12: Unicode 11.0 / Java SE 11: Unicode 10.0 / Java SE 9: Unicode 8.0 / Java SE 8: Unicode 6.2 / Java SE 7: Unicode 6.0 / Java SE 5.0: Unicode 4.0 / Java SE 1.4: Unicode 3.0 / JDK 1.1: Unicode 2.0 / JDK 1.0.2: Unicode 1.1.5
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