I am setting up a new Nexus 5X with Marshmallow. There does not appear to be a default mail application as in prior versions; instead there is just the GMail application. Is the Inbox by Google application what was formerly the stock mail application called "Email"?
No. Inbox is a very different application that was opened to the public in early 2015. It's primarily designed around the idea that your inbox is like a to-do list of sorts. The project's website explains this in more detail.
The "Android" email application is no longer developed by Google in any meaningful capacity, aside from ensuring that new platform releases do not break the build (and some translation updates, which are mostly automated). The Exchange and IMAP/POP features were instead rolled into Gmail, which is now considered the "stock" email application on any Google device.
Is the Inbox by Google application what was formerly the stock mail application called "Email"?
No, it is not.
As said already in earlier Answer, the support for Stock Email app is no more. I recently bought Moto G3 and it came pre-installed with Gmail with no other Email app.
Inbox is developed by Gmail team. Hence, all your messages from Gmail are with Inbox, along with the reliability and spam protection of Gmail.
But there are few advantages of Inbox over Gmail App.
- Creating a new labels: If you want to create new labels using Gmail app, it is not supported, Yet in Android. However, you can create new label using Inbox app.
- Inserting Images inline: Attaching inline images is not supported by Gmail, but you can attach images inline in the Inbox by Gmail app for Android.
But on flip side, Inbox does not support App widgets like Gmail app do.