Codebase Browser
chromium
Go to App

chromium/third_party/blink/web_tests/fast/multicol/nested-with-tall-block.html 

<!DOCTYPE html>
<p>There should be a hotpink <em>square</em> below.</p>
<div style="columns:5; column-gap:0; column-fill:auto; width:50px; height:50px;">
    <div style="columns:2; background:hotpink;">
        <div style="height:500px;"></div>
    </div>
</div>