Rational for this key? about webdriver

[whimboo]

The element identifier similar to ShadowRoot, window, and frame are relicts from the early implementations of Selenium we we kept it along to prevent backward incompatibilities. As such this also wont change anymore.

Note that for WebDriver BiDi a different serialization logic is used so that those arbitrary ids are not needed anymore, but are still internally shared by the browser to allow protocol interoperability.

[ioquatix]

My point was not to change them, but to add clarifications as to why they exist in the spec.