Did some more digging and found more info further back when the info was first requested. From the link above the entry fields:
"If your state identification number is less than 10 to 13 digits or you don't have one, add zeros (0) at the end of your employer's or payer's identification number and enter the number in the state identification column. This will meet Connecticut's 10- to 13-digit state identification requirement and ensure that your return gets processed as quickly as possible."
