fix: Editor assets endpoint enforces absolute URLs

[dcalhoun]

Proposed changes:

Enforce absolute URLs for the editor assets endpoint to avoid failed asset requests originating from the fact that clients send requests for their own origin. Relative URLs inherently fail as the client origin does not match the site origin, and the asset is unavailable on the client origin.

Other information:

• Have you written new tests for your changes, if applicable?
• Have you checked the E2E test CI results, and verified that your changes do not break them?
• Have you tested your changes on WordPress.com, if applicable (if so, you'll see a generated comment below with a script to run)?

Jetpack product discussion

N/A

Does this pull request change what data or activity we track or use?

No

Testing instructions:

1. Apply these Jetpack changes to your site (see comment).
2. Proxy your requests to your sandbox server.
3. Make a request to the /wpcom/v2/sites/<site_id>/editor-assets endpoint for the WPCOM site—via API Console, curl, etc.
4. Verify the 200 response does not include relative paths—e.g., /wp-includes/js/dist/vendor/lodash.min.js—but instead uses absolute URLs for these assets.

[github-actions]

Are you an Automattician? Please test your changes on all WordPress.com environments to help mitigate accidental explosions.

• To test on WoA, go to the Plugins menu on a WoA dev site. Click on the "Upload" button and follow the upgrade flow to be able to upload, install, and activate the Jetpack Beta plugin. Once the plugin is active, go to Jetpack > Jetpack Beta, select your plugin (Jetpack), and enable the fix/editor-assets-endpoint-enforces-absolute-urls branch.
• To test on Simple, run the following command on your sandbox:

bin/jetpack-downloader test jetpack fix/editor-assets-endpoint-enforces-absolute-urls

Interested in more tips and information?

• In your local development environment, use the jetpack rsync command to sync your changes to a WoA dev blog.
• Read more about our development workflow here: PCYsg-eg0-p2
• Figure out when your changes will be shipped to customers here: PCYsg-eg5-p2

[github-actions]

Thank you for your PR!

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• ✅ Add changelog entries to affected projects
  

This comment will be updated as you work on your PR and make changes. If you think that some of those checks are not needed for your PR, please explain why you think so. Thanks for cooperation 🤖

---

Follow this PR Review Process:

1. Ensure all required checks appearing at the bottom of this PR are passing.
2. Make sure to test your changes on all platforms that it applies to. You're responsible for the quality of the code you ship.
3. You can use GitHub's Reviewers functionality to request a review.
4. When it's reviewed and merged, you will be pinged in Slack to deploy the changes to WordPress.com simple once the build is done.

If you have questions about anything, reach out in #jetpack-developers for guidance!

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Jetpack plugin:

The Jetpack plugin has different release cadences depending on the platform:

• WordPress.com Simple releases happen as soon as you deploy your changes after merging this PR (PCYsg-Jjm-p2).
• WoA releases happen weekly.
• Releases to self-hosted sites happen monthly:
  • Scheduled release: October 7, 2025
  • Code freeze: October 6, 2025

If you have any questions about the release process, please ask in the #jetpack-releases channel on Slack.

[jp-launch-control]

Code Coverage Summary

Coverage changed in 1 file.

File	Coverage	Δ%	Δ Uncovered
projects/plugins/jetpack/_inc/lib/core-api/wpcom-endpoints/class-wpcom-rest-api-v2-endpoint-block-editor-assets.php	148/156 (94.87%)	0.24%	0 💚

Full summary · PHP report · JS report

[kean]

I reviewed the code – the changes look good, with minor nit. I didn't test it.