My hiking boots have a D-shaped ring at the base of the tongue. What is the purpose of this?
I don't think the purpose is to allow you to hang the boot on a hook or something, because there is a bigger strap on the back of the boot that would allow you to do that.
Or is the D-shaped ring purely decorative?
That is a loop for the hook on gaiters. The gaiters will cover the upper foot and laces on the boot, which helps prevent snow and mud build-up on the boot as well as prevent stones/sand/etc getting into the boot itself.
The hook on the gaiters goes through this loop and keeps the gaiter in place, otherwise it will slide up the foot.
