SE17's specification of javax.lang.model.SourceVersion methods
https://docs.oracle.com/en/java/javase/17/docs/api/java.compiler/javax/lang/model/SourceVersion.html
uses "restricted keywords and restricted identifiers" terms.
Methods that use these terms refer to Java Language Specification.

However JLS17 doesn't mention "restricted keywords" or "restricted identifiers" any more; instead the new term seems to be "contextual keywords"
https://docs.oracle.com/javase/specs/jls/se17/html/jls-3.html#jls-3.9

"restricted keywords" / "restricted identifiers" are present in JLS16
https://docs.oracle.com/javase/specs/jls/se16/html/jls-3.html#jls-3.9

"restricted keywords" first appeared in JLS9
https://docs.oracle.com/javase/specs/jls/se9/html/jls-3.html#jls-3.9