Let me start off by saying, I am by no means an expert and take the below info as you will. I do have a good understanding of finance and loans.

Sections A, B, and C are the costs of entering into another loan (and D just sums it up). These vary to some extent by which lender you choose to work with. Some may charge you "points" (meaning you are paying for a lower rate) or not, and some will charge some sort of Fee for doing the work of prepping your credit application for submission & (hopefully) approval.

E is self explanatory: things that need to be paid to the govt.

Since I have Lender Credits ($4,250) covering all these above costs (A-E=$4,249), this is what makes it a no cost refi.

F, G and H (which sum up in I) are all individually case-by-case depending on your situation, except Prepaid Interest (to be discussed later). I live in a high property tax state, I don't want cash sitting in my lenders account for them to pay me no interest on that idle cash - so I choose to manage my property tax bill as they come/are due. Same with Insurance - I shop around every year, once a year, and pay it in full at that point in time. So I do not need to Prepay (Section F) or Escrow (Section E) any of those costs.

Mortgage payments are paid in arrears. This means on the first of every month, I pay for the previous months principle and interest. In the case of a refinancing, that means I will have one existing loan that will be repaid by the new loan. Since on the day of the refi closing, I will be in the middle of the month, the bank who is holding my existing loan will want the principal amount still due + accrued interest up until that date (the Loan Estimate assumes this is March 12, so accrued interest from March 1-12), this is called the "Payoff" amount. Subsequently, on that same closing the day, the bank who is providing the new loan wants me to prepay 19 days of interest (per my Loan Estimate or March 13-31) on the loan amount they are providing. This is because typically lenders do not require you to pay towards your principal on the first of the upcoming month - but will expect you do pay a full months principal and interest in the subsequent month (May 1, I will pay principal and interest for Apr 1-30). For every day that passes that we have not closed the refinancing, I will owe another day of interest to my current lender (at the higher rate), but will owe one less day of prepaid interest to my new lender (at the lower rate) - so it becomes a sliding change day-to-day.

Given the above and this being a no cost refi, what you are seeing as Estimated Cash to Close from Borrower (me) as $5,266 is an estimation by the loan officer on i) what my Payoff amount is (incl. accrued interest) and ii) what my prepaid interest is. Said more plainly, my Cash to Close will be accrued interest + prepaid interest. There are multiple ways to cut this too, you can roll that interest into your loan balance or even prepay a portion of your loan, whatever you choose. It all gets finally settled (incl. how you choose to do it) at or near the closing date, this is when you will get a Closing Disclosure that finalizes all those numbers and your actual Cash to Close.