demo · v138

Popup prewarm

The case the field was added for: prerendering a page that the user will eventually open in a new tab. Without target_hint: "_blank", the browser warms a same-tab context and has to throw the warm copy away when the actual click is middle-click or has target="_blank". With the hint, the warm context already has the right shape.

user clicks "open in same tab"

awaiting…

user middle-clicks — new tab

awaiting…

the rule

<script type="speculationrules">
{
  "prerender": [{
    "urls": ["/checkout"],
    "target_hint": "_blank"        // NEW in 138
  }]
}
</script>

The hint tells the browser which top-level browsing context to pre-allocate the prerender for. A page that knows its CTA is a target="_blank" link can hint "_blank" and avoid a throw-away warm-up.

see also