See https://bugzilla.mozilla.org/show_bug.cgi?id=230307#c14: everyone except Gecko copies the value and presumably dirty value flag. I have not tested whether it's the raw value that gets copied or whether the raw value on the clone gets set to the API value on the original.
See https://bugzilla.mozilla.org/show_bug.cgi?id=230307#c14: everyone except Gecko copies the value and presumably dirty value flag. I have not tested whether it's the raw value that gets copied or whether the raw value on the clone gets set to the API value on the original.