Postqueue

In the block editor, in the document sidebar next to the other post settings - the same place the permalink and the categories live. It behaves like the category panel: ticking a queue marks the post as changed, and the change is written when you save or update the post. Nothing is sent while you are still clicking. You can create a queue right there too, the way you add a category: the Add new postqueue link opens a name field. Creating happens immediately - only the assignment waits for the post to be saved. A search field appears once there are more than eight queues, filterable with postqueue_panel_search_threshold. The classic editor keeps the meta box it always had. Only one of the two appears, never both.

Under Tools → Postqueues. The overview is the same kind of table WordPress uses for posts and pages, with a search box, sortable columns and bulk deletion, and a form next to it for adding one. Opening a queue shows its posts in order. Inside a queue you can reorder by dragging, or with the Move up and Move down buttons - those also work from the keyboard. The order is applied when you press Save; leaving the page with unsaved changes asks first.

Insert the Postqueue block. It is a variation of the core Query Loop, so it comes with the same pagination, layout options and Post Template inner blocks as any other loop - pick a queue in the block sidebar instead of a category. The posts appear in the order the queue defines, and an empty queue outputs nothing rather than everything. The [postqueue] shortcode and the theme templates still work as before: [postqueue slug="my-queue" viewmode="" offset="0" limit="-1"]. Only slug is required; viewmode is one of the view modes registered with postqueue_viewmodes, offset skips that many posts, and limit caps how many are shown (-1 for all).