The email application is currently showing a mode startup time of 150-175ms in Datazilla  for moz-app-visually-complete. To me this doesn't seem realistic in comparison with some of the other applications.  https://datazilla.mozilla.org/b2g/?branch=master&device=flame&range=7&test=startup_%3E_moz-app-visually-complete&app_list=email%20FTU&app=email%20FTU&gaia_rev=e347a0f1ffa02d5a&gecko_rev=2173f64091e3&plot=avg
Running the tests for Datazilla apparently uses the `make reference-workload-light` script, which doesn't have any jobs for the email app. Maybe adding a workload script for email would make the startup appear more realistic for what typical users see.
The email app also has a large initial launch time but subsequent lower launch times due to cookie caching at first launch. The solution here should clear their cookies for cold launches.
This should be resolved when Raptor implements the first-launch phase.