Just looking around at stuff in the Armory on B.net, I noticed the "Reforge" icon and text on some armor (all TTK armor, actually), and specifically this helmet I knew I currently had:

But when I actually looked at the helmet on my Hunter, the icon is missing...

Sooooo....what am I missing? I remember this being talked about, and there's a bunch of "this could be a thing" posts if you Google the topic, but I didn't find any examples (yet) of this actually being done, or how it works (if it does).

Does it show up differently in-game?

Is there no "node" but the feature is still there, only at the appropriate vendor? Who is the appropriate vendor?

Anyone know anything more about this?

... I'd say it is a feature that is currently buried in the back end. Remember when they added weapon reforging in HoW, but we could't reforge vanilla or TDB guns? I think Bungie is planning ahead here. They might add armor reforging at some point down the road, so they've put all the back-end hooks in place to make all TTK armor reforgeable if/when they add the feature.