So far in Spring Framework 6 does not exist an official list of the reserved words or Predefined Variables with their respective explanation about SpEL. I think is important create that list, because it brings the official information about how work each one and if is added in the future a new Predefined Variables therefore, it is updated and listed according for each SF version

Just in case, question done in SO at:

Thanks for your understanding

Comment From: simonbasle

answering on stack overflow

Comment From: manueljordan

Thank You

Added a note on SO - in the original post.