Safari/Chrome/Firefox: Caret Rendering inconsistent with empty placeholder across browsers

Caret placement with pseudo element and br tag

In Chrome when we render a pseudo element as "placeholder" we expect the caret to render in front of the multiline pseudo element in an empty html element (contenteditable) (should also work with text-align: center)

<style>
[placeholder].empty::before {
  content: attr(placeholder);
}
</style>
<div class="empty" contenteditable="true" placeholder="Hello"><br></div>

Actual behaviour:
in Chrome: Caret is rendered in last line after the last character of the placeholder
in Safari: Caret is rendered in last line before the first character of the last of the placeholder

Repro: https://w3c.github.io/editing/repros/498.html

Start with the linked repro at https://w3c.github.io/editing/repros/498.html and inspect the contenteditable example using a pseudo-element placeholder and br tag. Compare caret placement in Chrome, Safari, and Firefox, including the centered text case. Done means the expected caret behavior and any required specification or repro updates are agreed and documented.