You can add comments to your expressions by enclosing them in braces { }, for example:
{This is a comment. It allows you to advise other users about the expression without affecting how the expression is processed}.
The purpose of comments is to allow you to leave useful information about the expression within the expression code. The comment can then be read by other users who are examining the expression code. For example, if part of an expression is particularly complex or produces an unexpected result, you can add a comment to that part of the code to explain how it works to other users. Any text that is inside the braces is treated as a comment and will not affect the validity of the expression in any way.