It's the traditional formal signoff where the recipient is not addressed. I understand it is of British origin. My guess as to its meaning is, since it is not a

It's the traditional formal signoff where the recipient is not addressed. I understand it is of British origin. My guess as to its meaning is, since it is not addressed, you are faithful to the recipient that it will get to the right place. When I send correspondence externally, it is formal in nature. I have just followed templating conventions. I think it is out of place for less formal communications.