Backtick language lawyer question

If you look part where output of argument as a function is shown http://code.kx.com/wiki/Reference/value you will see the globals has out as `d. Question is why is the variable name which is just d has a backtick before it. The variable d does not have a backtick before it in the function body. A general question is why is a backtick required during enumeration or when refering to a foreign key. I guess this is a language lawerly question but would appreciate some input.

d is the name of the variable. If you write d the value is referenced.  thats also the reason why you do updates  with  "update x:1 from tbl"
while writing  “update x:1 from tbl”  does NOT update the table but return a new one.

value of a function returns the globals used, if it would output “d” instead of “`d” the interpreter would instantly

change d with the value in it.. thus you would not see the actual reference..