I guess this means Tumblr is coming to the fediverse?

There has been some signs and rumours to that effect since Mastodon started taking off; I believe Automatttic specifically advertised for ActivityPub developers to work on Tumblr?

But Tumblr moving on to a Wordpress base only opens for the option of federation, if that is even accessible in the Wordpress installation that will drive Tumblr — as I understand it. Or has the WP-ActivityPub plugin been rolled into core WP without me noticing?