Gutenberg is a feature that has been under development for a while now, will be released with version 5 of WordPress in the very near future. Until that time, it can be installed as a WP Plugin if you want to try it out. I'm pretty excited about this, cause it looks pretty awesome to me. The designers are already thinking ahead, and here is how they see the future of the internet and what Gutenberg's role will be in this.
