> enhanced selector engines that pierce shadow DOM by default It’s worth noting, for those that don’t realise it, that from client-side scripting you can’t rel

> enhanced selector engines that pierce shadow DOM by default It’s worth noting, for those that don’t realise it, that from client-side scripting you can’t reliably pierce the Shadow DOM. Playwright must be doing this with privileged APIs. Specifically, although element.attachShadow({ mode: "open" }) sets element.shadowRoot to the ShadowRoot that it returns, element.attachShadow({ mode: "closed" }) only returns the root, and you can throw that away or store it in a private property or closure variable or whatever, so that it’s impossible to access from outside. Yes, shadow roots give you an inviolable membrane (and one that I don’t think content blocker are piercing yet, because not many sites have been abusing it yet). The only way outside code will even be able to discern that there is a closed shadow root is by trying to create one and having that fail (which is a canary, you can only do it once).