<!DOCTYPE html>
<body>
<script>
let resolverCalls = 0;
document.evaluate("/foo:bar", document.documentElement, () => {
resolverCalls++;
return "http://www.w3.org/1999/xhtml";
});
console.log(resolverCalls)
</script>
</body>
Firefox logs
1(good), servo logs2(bad).