Non-standard: This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.
Note: This API is available only to WebExtensions.
property represents the shadow root hosted by the element, regardless if its
Element.attachShadow() to add a shadow
root to an existing element.
This property is not part of any specification.
BCD tables only load in the browser