Unwanted Pintererest code in WP HTML

I noticed a Html code in my WP posts. Where does that come from? Because I don’t think I have any plug in what place codes like below.

My site is mallware checked and clean. Anybody known with this issue?

Site: https://www.verenigdestaten.info

<a href="https://nl.pinterest.com/pin/create/extension/" style="height: 20px; width: 40px; position: absolute; opacity: 0.85; z-index: 8675309; display: none; cursor: pointer; background-image: url('data:image/png;base64,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');"></a>