Spec assumes entire app is self-contained and requires a consistent display mode

[marcoscaceres]

Elsewhere, Mark Taylor wrote:

Specification assumes that the entire app is self contained and requires a consistent
display mode

Most web apps will have both internal links (to other parts of the web app), and external
links to elements outside of the web app. External links often do not contain a route back
to the web app, so the preferred behaviour is either for it to a) launch in the web browser,
or b) launch within the app, with a navigation element allowing users to return to the
web app.