jn:jsoniq-boolean-and-null-literals is available ("yes" or "no"), that activates or deactivates the interpretation of a standalone NameTest "true", "false" or "null" (meaning: occurring as a PathExpr, i.e., no slashes, no axes) as boolean and null literals. By default, it is set to "yes". [6]
true, false, or null must use the ./ construct, as in ./true.