i.e. it was developed independently, but Automattic bought the plugin and hired the developer. Apparently, it'll eventually be integrated into Wordpress (probably through Jetpack - my assumption).
I use it, it basically allows people to follow your Wordpress blog through any Fediverse account, just like any other Fediverse account. You can decide if the full post gets pushed in followers feed, or just an excerpt, or just a link, etc, a bit like RSS.