What is the "Your Requested Refund" box on my Virginia state return?

When filing my Virginia state return, TurboTax took me to a secondary page for "Other Required Information", where there is an empty box asking me for my "requested refund amount".

 

What does that question mean?

 

For context, I am a DC resident who commutes to Virginia for work, and I don't expect to owe any Virginia taxes due to Virginia's reciprocity rules with Washington DC.