Created attachment 742310 [details] screenshot Do we even need this page? if yes, we need to make it look pretty.
Created attachment 742348 [details] Payment complete progress screen This screen is also in the documentation found in this bug: https://bugzilla.mozilla.org/show_bug.cgi?id=856827#c0
Yes, we need it because the Mozilla server needs to receive a redirect from Bango. However, this screen can be blank or maybe it can show a loading indicator like bug 866047. It will only be shown for a few seconds and then the Trusted UI will be closed automatically and the app will be installed.
The mock looks good to me. I don't think we can make it transparent though. We cannot show the marketplace in the background because the Trusted UI window is not transparent.