Unknown field in panic stack trace

In trying to learn how to debug stack traces from panics, I came across something confusing.

package main

func F(a int) {

func main() {

outputs the following when I run it on the attached play link:

panic: nil

goroutine 1 [running]:
main.F(0x1, 0x10436000)
    /tmp/sandbox090887108/main.go:4 +0x20
    /tmp/sandbox090887108/main.go:8 +0x20

I can’t decipher what the second number means (the 0x10436000 in main.F(0x1, 0x10436000)). It doesn’t appear if there’s a second int argument, or if anything else if passed in as the first argument (can be seen in the second play link).

One arg: https://play.golang.org/p/3iV48xlNFR

Two args: https://play.golang.org/p/4jA7ueI86K