If a format suffix is present in the path, selecting a different format in the browsable API does not work.

[SvenMoenig]

In the browsable API, if the format is specified via a path-suffix, the dropdown to force a different format does not work, because it only determines the request parameter.

For example, if the path is /endpoint.api?format=csv, the BrowsableAPIRenderer will be selected to render the request.
However, the dropdown through which the user can specify a different format to be used does only replace the csv in the above example.

Ideally both should be overridden, or at least the .api should be removed, so that the format selected by DefaultContentNegotiation is the one selected by the user.