Documenting Expressions
You can add comments within your expression in order document and describe what they do.
This can be useful both when revisiting expressions that you'd written some time ago, and also help other solution builders who may need to maintain, modify the expression in understanding what they do.
Comments are added be using a # character at the start of the line. If you're comment spans multiple lines then you must use a # character on each line.
# Retrieves the name of the engineer and records it
# for audit purposes as the originator of the fault
=INFO("user.firstname") & " " & ("user.secondname")