First of all, that isn't a LAN to WAN setting of Reject. The enable LAN to WAN is the graphic to the Left of that - under the column "Zone => Forwardings". That entire row is the Zone-based firewall settings for LAN. Each row configures the Zone named on its extreme Left. I believe LAN was accept intra-zone forwarding by default (more on how to find out below).
Nonetheless, what you circled is the forwarding of a packet FROM THE LEDE TO ANOTHER ROUTER IN THE SAME ZONE. Most consumers don't use 2 routers in the same firewall zone (unless one is doing NAT).
See: https://wiki.openwrt.org/doc/uci/firewall
To get your answer, simply backup the config, erase the router and see the setting. I honestly don't have a device in default configuration to check for you. From a device that I don't beleive I had to reconfigure, LAN is: Input (from LAN to router) accept, Output (from router LAN IP) accept and Forward (to other subnets in zone) accept.