In the windows firewall, a arrow in front of the rule indicates that the rule is already enabled

Green Check Mark.

Explanation:

A Firewall on a Window’s PC has inbound and outbound rules that are set to either allow or block access to other devices and programs. Inbound rules allow traffic from within the network or outside of the network into your computer while outbound rules is the vice versa from your computer to the network. The rules that have a green check mark means that they are enabled and are currently being used by the firewall while those that have a gray check mark are disabled manually or by default to mean that they are not being used by the Windows Firewall