Optional ReadonlydomainURIs of the scopes in which this change applies.
Optional ReadonlynewThe new value of the changed preference.
Can be undefined for multiple reasons:
undefined, use the preference service to determine the effective new value if needed.Optional ReadonlyoldThe old value of the changed preference.
ReadonlypreferenceThe name of the changed preference.
ReadonlyscopeThe PreferenceScope of the changed preference.
Representation of a preference change. A preference value can be set to
undefinedfor a specific scope. This means that the value from a more general scope will be used.