Shadow DOM element location limits with getShadowRoot()

Selenium 4 introduces the getShadowRoot() method to address the encapsulation of the Shadow DOM, which previously prevented standard findElement calls from accessing internal elements.

While this method allows access to the shadow root of a host element, the interaction model changes. Element searches must be performed against the returned root object rather than the global driver instance. Furthermore, the Shadow DOM specification restricts the types of selectors that can be used to locate these internal nodes.

When dealing with deeply nested shadow roots—where a shadow host exists inside another shadow root—the process requires recursive access to each level of encapsulation.

• Does the getShadowRoot() implementation support XPath for locating elements within the root, or is it strictly limited to CSS selectors?
• What is the documented behavior for handling nested shadow roots across different browser drivers?