If what we hear is authentic, soon we will get some fundamental features in our next Nexus Phones. These changes will hit the market with 2016 Nexus Phones and can be a step towards the Android 7.0- Nougat as the launcher.
The changed attributes appear to correspond to the Google CEO, Sunder Pichai's statement. Sunder Pichai-"The company, is planning on getting more opinionated with its Nexus offerings".
The changes suggest two probable things. First is that company is making its way to the Android 7.0 Nougat. Or, maybe the launcher is going to work on even non-Nexus Phones. Reports don't claim this to be final from Google's side, but the search giant is sure moving forward with the animated feature change and Promoting its Google Assistant.
As the leaks suggest, Google has superseded the Home Button with an animated Home Button on the screen navigation keys. We saw a gif manifesting that when long pressed, the Home Button splits into four dots with rapid animation just as seen in Google Assistant. Also if Google Now turned off, the animation will vanish.
Currently, Google now works on tap but as Google Assistant is still under development stage and is expected to arrive with next Nexus Phones. So maybe animation can provide an option to tap into Google Assistant.
Another change reported is the change of the colour theme of settings menu to a dark grey, blue, and white UI. The settings tab got split into 'Support' and 'All' sections, a feature exclusive for next Nexus Phones only. The name of 'Night Mode' becomes 'Night Light'. Additionally 'Quick Screen Check' is an aid to check our notifications without awaking our phone.
Nothing is official, and the above information is just leaked report. We still are waiting for any official announcement.