User blog comment:Dragonjet/KC3改/@comment-89.86.52.63-20150925123334/@comment-1820055-20150928054346

I'm quite sure it was added on the webstore release right after it was implemented. It's only for natsuiro theme though. The icon in the Reinforcement Expansion slot should be on their faces. I can't get a screenshot right now though, I haven't used any of my expansions.