2.9 For identified but unsupported natural languages, notify the user of language changes when configured to do so. 7.8 Allow the user to configure structured navigation. 3.10 Allow the user to turn on and off automatic content refresh. 8.6 Allow the user to configure the outline view. 8.9 Maintain consistent user agent behavior and default configurations between software releases.
Consistency is less important than accessibility and adoption of operating system conventions.
10.6 Provide default input configurations for frequently performed operations. 10.7 Allow the user to configure the graphical arrangement of user interface controls. 8.7 Allow the user to configure what information about links to present. 9.4 Allow the user to configure notification preferences for common types of content and viewport changes.