Adding the following to your config.php:

$CFG->customfiletypes = [

    (object)[

        'extension' => 'webp',

        'icon' => 'png',

        'type' => 'image/webp',

        'groups' => ['image', 'web_image', 'optimised_image'],

        'string' => 'image'

    ]

]; 

The new ad-hoc task and the utility function in the upgradelib are both covered by unit tests.

Before patch

1. Log in as administrator
2. Under "Administration → Plugins → Repositories → Manage repositories" set Legacy course files to "Enabled and visible"
3. Under "Administration → Plugins → Repositories → Common repository settings" set "Legacy course files in new courses" to "Yes".
4. Under "Administration → Courses → Default settings → Course default settings" set Legacy course files to "Yes".
5. Add a new course.
6. Go to "More → Legacy course files"
7. Upload file_example_WEBP_50kB.webp
8. Note the file icon has the question mark.

After patch

1. Update to this code, run an upgrade, run cron.
2. Re-visit the course "Legacy files" section
3. Verify the file has now the image icon.
4. Go to "Site administration" → "Server" → "File types"
5. Verify webp is there and listed as any other image file type, e.g. tiff.

Code verified against automated checks.

Checked MDL-81437 using repository: https://github.com/ziegenberg/moodle

• main (0 errors / 0 warnings) [branch: MDL-81437_allow-webp-file-extension-by-default | CI Job]

_{More information about this report}

Built on: Mon Mar 31 15:27:00 UTC 2025

Launching automatic jobs for branch MDL-81437-main

• https://ci.moodle.org/view/Testing/job/DEV.02%20-%20Developer-requested%20PHPUnit/18464/ PHPUnit (sqlsrv)
• https://ci.moodle.org/view/Testing/job/DEV.01%20-%20Developer-requested%20Behat/63231/ Behat (NonJS - boost and classic)
• https://ci.moodle.org/view/Testing/job/DEV.01%20-%20Developer-requested%20Behat/63232/ Behat (Firefox - boost)
• https://ci.moodle.org/view/Testing/job/DEV.01%20-%20Developer-requested%20Behat/63233/ Behat (Firefox - classic)
• https://ci.moodle.org/view/Testing/job/DEV.01%20-%20Developer-requested%20Behat/63234/ App tests (stable app version) --> unrelated failure, please ignore.

Built on: Fri Mar 7 06:25:59 UTC 2025