What are the main features of Android M?

As per the announcements made by Google at I/O event, here is the list of possible newer features -

Native Fingerprint support -
There will be a native support for fingerprint scanner via API. This will help even the low end phones to have fingerprint scanners. This will enable phones to enable mobile payments.

Android Pay -
Android Pay is likely to come up with the launch of Android M. Google is making the mobile payments more safer.

Change in app permissions -
Google is planning an increased user control on app permissions. "In context" app permissions are being introduced.

Better Web experience -
Chrome will now have custom tabs on Android M. Developers can enable Chrome overlay on app settings

Improved app links
Improved Web links will help apps to handle the internal Web links with ease. That way users will not have to deal with ambiguous pop ups. The app itself will decide whether the links need to be opened by in app browser or any other external app.

Power Management -

Android M will introduce Doze feature to extend battery life. The OS will detect when the device is lying idle and limit the background activities to improve battery life.

New RAM manager -
The new RAM manager will show the amount of memory being consumed by apps and accordingly rate them as good or average. This helps identify RAM hungry apps so that the user can get rid of them and bring it to the notice of the developers.

New app drawer -
The scrolling will now be vertical instead of horizontal. Design and color will remain similar to Lollipop.

Backup and Restore of App data -
In a best move, Google M will support backing up and restoring app data. Thus will be helpful for users who tend to change devices regularly , or those formatting their devices frequently.

These are some good features that have been showcased in the preview to the next gen Android platform. Actual picture will be clear when the next version launches.