[Step 1] Custom colors: stop serving discontinued COLOURLovers backgrounds

[Copons]

Proposed changes

• COLOURLovers support has been discontinued. On Atomic sites, a background image set from a COLOURLovers pattern is stored on the COLOURLovers S3 bucket (colourlovers.com.s3.amazonaws.com) and emitted straight into the page, so every visitor's browser requests it on each load. This adds a theme_mod_background_image / theme_mod_background_image_thumb render filter (Colors_Manager_Common::remove_colourlovers_background()) that blanks any colourlovers.com.s3.amazonaws.com or colourlovers-static-replica.s3.amazonaws.com URL, so those requests stop.
• No fallback is provided — empty/broken backgrounds are acceptable. The stored theme_mod is left untouched and only blanked at render time, so a site shows no background until its owner picks a new one.
• The filter is attached before the enable_custom_customizer guard, so the requests stop even where the rest of the custom-colors tool is disabled.

Related product discussion/links

• Related to DOTCOM-1758

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

No.

Testing instructions

• On an Atomic site, switch to a classic theme that supports custom backgrounds (e.g. Twenty Fifteen).
• Give it a COLOURLovers background image, e.g.:
  • wp theme mod set background_image "https://colourlovers-static-replica.s3.amazonaws.com/images/patterns/5814/5814723.png"
  • wp theme mod set background_image_thumb "https://colourlovers-static-replica.s3.amazonaws.com/images/patterns/5814/5814723.png"
• Before this change: load the front end → the #custom-background-css block contains that URL and the browser requests it (visible in DevTools → Network).
• After this change: reload → the custom-background block is gone, get_theme_mod( 'background_image' ) returns empty, and no request is made to either COLOURLovers host.

[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 (WordPress.com Site Helper), and enable the dotcom-1758-stop-the-colourlovers-feature-from-working branch.

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
  

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Wpcomsh plugin:

• Next scheduled release: Atomic deploys happen twice daily on weekdays (p9o2xV-2EN-p2)

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/wpcomsh/custom-colors/colors.php	0/814 (0.00%)	0.00%	7 💔

Full summary · PHP report

_{Coverage check overridden by I don't care about code coverage for this PR Use this label to ignore the check for insufficient code coveage. .}

[Copilot]

Pull request overview

This PR updates the wpcomsh “custom-colors” functionality to prevent Atomic sites from continuing to serve (and therefore request) discontinued COLOURLovers-hosted background images by blanking those theme mods at render time.

Changes:

• Add render-time filters for theme_mod_background_image and theme_mod_background_image_thumb to blank COLOURLovers S3 URLs.
• Introduce Colors_Manager_Common::remove_colourlovers_background() to detect and remove legacy COLOURLovers background image URLs.
• Add a wpcomsh changelog entry documenting the behavioral change.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
projects/plugins/wpcomsh/custom-colors/colors.php	Adds unconditional theme-mod filters and a helper to blank COLOURLovers background URLs at render time.
projects/plugins/wpcomsh/changelog/dotcom-1758-stop-colourlovers-backgrounds	Documents the change in wpcomsh’s changelog system.