custom-background.php in WordPress 5.3.21

Use CoreFiles from your AI agent

# CoreFiles

> The original files of every Joomla and WordPress release, run by mySites.guru. Free, no API key, read-only GET requests.

Use it to tell whether a file on a Joomla or WordPress site is an unmodified core file, which release it came from, and what changed between releases. Hash the site's files where they are and send only the hashes; never upload a site's files.

Base URL: https://corefiles.mysites.guru
Platforms: joomla, wordpress. Versions as released, for example 5.4.0, 6.2.0-rc1, 7.1.4.
Add ?format=json to a page URL (/lookup, /pretty, /folder, /history, /diff, /stats) for the same data as JSON.

## Look up a file by its hash

GET /lookup/{md5 or sha256}?format=json&name={file name}
Lists every release and path that has this content. No matches means it is not a core file in any stored release. With name, "named" lists core files that have that file name, so you can fetch the original and compare.

## Read a core file

GET /raw/{platform}/{version}/{path}        the file's bytes
GET /stat/{platform}/{version}/{path}       md5, sha1, sha256 and size as JSON
GET /history/{platform}/{path}?format=json  the releases where that file changed

## Compare releases

GET /diff/{platform}/{from}/{to}?format=json         added, removed and changed files
GET /diff/{platform}/{from}/{to}/{path}?format=text  a unified diff of one file

## Check a whole site

GET /hashes/{platform}/{version}/plain
Every core file in that release as path<TAB>md5. Hash the site's files and compare: a different md5 means a modified core file, and a file missing from the list is not core.

## Reading the answers

A 404 with X-Corefiles-Release: present means the path is not in that release, so the file is not core.
A 404 with X-Corefiles-Release: missing means that release is not stored yet. Treat the answer as unknown, never as "not core". New releases are added within the hour.
GET /releases.json lists every stored release.

Paste it into Claude, ChatGPT or Cursor. Agents can also read it at /llms.txt. On a lookup, file, history or compare page, Copy for your AI agent adds what that page shows.

custom-background.php15 lines, 419 bytes, from wordpress-5.3.21.zip

Raw History Compare with 5.3.20

md5: 1263b5886047f8dc10ac8d025bbfc99e
sha1: 1a1ba70366a91037c6ed1a34c1231d8096f8cc98
sha256: 1b31e05580f6a98a5c905ceba0c96216373f55829005c8ebbbb96c16653bb78c

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

<?php
/**
 * Custom background script.
 *
 * This file is deprecated, use 'wp-admin/includes/class-custom-background.php' instead.
 *
 * @deprecated 5.3.0
 * @package WordPress
 * @subpackage Administration
 */

_deprecated_file( basename( __FILE__ ), '5.3.0', 'wp-admin/includes/class-custom-background.php' );

/** Custom_Background class */
require_once( ABSPATH . 'wp-admin/includes/class-custom-background.php' );

The same content is in 39 releases, WordPress 5.3-beta1 to 5.3.27. See them all, or every version of this file.