Description

wp.editPost.__experimentalPluginPostExcerpt was exposed as an accessible API in WordPress 6.5 and subsequently deprecated in #61188 with a no-op function.

This breaks backward compatibility for extenders using the API so the deprecation needs to be fixed to provide a shim for the recommended process for adding content to such panels.

Step-by-step reproduction instructions

POC plugin:

import { registerPlugin } from '@wordpress/plugins';
import { __experimentalPluginPostExcerpt } from '@wordpress/edit-post';

const PwccPostExcerpt = () => {
	return (
		<__experimentalPluginPostExcerpt className="pwcc-post-excerpt">
			Post Excerpt - Custom content
		</__experimentalPluginPostExcerpt>
	);
}

registerPlugin( 'pwcc-post-excerpt', { render: PwccPostExcerpt } );

1. Create and build the POC plugin above.
2. Checkout 4abdb39 or earlier
3. Create a new post and open the excerpt panel
4. At the bottom of the panel the text "Post Excerpt - Custom content" will display
5. Checkout trunk
6. Create a new post and open the excerpt panel
7. The plugin's text will no longer be displayed

Screenshots, screen recording, code snippet

WordPress trunk

Gutenberg 4abdb39

Gutenberg trunk

Environment info

• WordPress/WordPress master at 9a2a3dc5b3ed97ae7a894b65576227b033ec0e86
• Gutenberg trunk at 5b154e5

Please confirm that you have searched existing issues in the repo.

Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

Yes