Embedded app navigation bar use cases

[artooras]

The documentation on embedded app navigation bar is rather limited, so I'd like to ask about some use cases to understand if this approach supports them.

1. Can the navigation bar be displayed conditionally? Meaning that if after the user installs the app I want to take them through a signup process - say, on a /signup path - can the navigation bar be hidden?
2. How is the current link determined? Is it based on the path match?
3. (optional) is it possible to add additional elements (e.g. a tag), in navigation links?
4. (optional) do navigation links support translations?