A post on Reddit allegedly contains a screenshot of a Gmail app interface that integrates many features taken from Inbox. They include a pinned-only toggle, per-subject bundling and Assistant-esque reminders. They may have been picked for preservation by Google before Inbox shuts down for good.
https://www.notebookcheck.net/New-Reddit-leak-suggests-Gmail-will-gain-more-Inbox-features-soon.402891.0.html
This does sound good but where is the select all feature that's in the web version?