Where you can’t see, hence debts shine sort of (6,3,6)
I believe the answer is:
behind the scenes
'where you can't' is the definition.
The definition suggests a singular noun but the answer is not.
'hence debts shine sort of' is the wordplay.
'sort of' indicates anagramming the letters.
'hence'+'debts'+'shine'='hencedebtsshine'
'hencedebtsshine' anagrammed gives 'BEHIND THE SCENES'.
'see' acts as a link.
Can you help me to learn more?
(Other definitions for behind the scenes that I've seen before include "responsible for acts, partly" , "in the private sector" , "Playwright is" , "out of public view" , "Where stage hands work" .)