Add blueprint to enable Gutenberg Guidelines experiment

[smithjw1]

Summary

Gutenberg Experiments page and drops the user directly on the Guidelines admin
screen.

What it does

1. Installs the Gutenberg plugin
2. Runs a PHP snippet to toggle on the gutenberg-guidelines key in the
   gutenberg-experiments option
3. Lands the logged-in user on /wp-admin/admin.php?page=guidelines-wp-admin

Testing

Preview in WordPress Playground:
https://playground.wordpress.net/?blueprint-url=https://raw.githubusercontent.
com/smithjw1/blueprints/trunk/blueprints/gutenberg-guidelines/blueprint.json

• Gutenberg plugin is active
• Gutenberg → Experiments shows the Guidelines experiment checked
• Landing page is /wp-admin/admin.php?page=guidelines-wp-admin

[github-actions]

Test using WordPress Playground

The changes in this pull request can previewed and tested using a WordPress Playground instance.

WordPress Playground is an experimental project that creates a full WordPress instance entirely within the browser.

Some things to be aware of

• All changes will be lost when closing a tab with a Playground instance.
• All changes will be lost when refreshing the page.
• A fresh instance is created each time the link below is clicked.

For more details about these limitations and more, check out the Limitations page in the WordPress Playground documentation.

[bph]

Using the blue "Test with Playground button" the blueprint fails with this error message:

Could not download "https://downloads.wordpress.org/plugin/gutenberg.latest-stable.zip".

Confirm that the URL is correct, the server is reachable, and the file is actually served at that URL. Original error:
TypeError: Failed to fetch

BlueprintStepExecutionError: Error when executing the blueprint step #2: Could not download "https://downloads.wordpress.org/plugin/gutenberg.latest-stable.zip".
Must be a problem with the tools

Using the blueprint in a new playground instance, it works well.

Screen.Recording.2026-05-07.at.12.09.15.mov

Thank you so much for your contribution @smithjw1 - I merged it and it should be available in the Blueprint list shortly.