There's a Chrome Extension he made based on this: https://anatolyzenkov.com/stolen-buttons/button-stealer

I used it for a bit until I realized... I probably didn't want a third party reading all my traffic. But I did like having it for a bit.

(It is linked from the page, but given how the whole page is CTAs... it's hard to notice!)

Why I third party? Aren’t the stolen buttons stored locally?