There are 29975 webp images at commons. The bub applies to all of them - not all come with EXIF, XMP or ICC data - but you cannot see, witch do have metadata, as it is never shown on the file description page. You would need to download webp files and inspect with exiftool fo find out.

But as a test case: I have uploaded File:Meintest.webp (now deleted again, as the included Metadata does not show online) it contains plenty EXIF, XMP and ICC data: F-number, ISO number, copyright info, author info, comment files and more. This metadata is includud in the thumbs - however you have to download and inspect the thumbs with exiftool to actually see it.

You can enter a mediasearch at commons and then choose "webp" from the file format drop down menu in the results to find any webp, The one's with photo content are more likely to include EXIF than logos or graphics (and many may be COPYVIO as the EXIF that could be hinting to the copyright is invisble at commons).

Or you can undelete Meintest.webp to get a webp file with rich metadata for testing.

@C.Suthorn: Okay. Can you please provide a link to an example? You probably found this problem on some page so it should be easy to copy and paste your link here, compared to someone else going to Commons and having to search for webp images. Please always include links. Thanks.

https://commons.wikimedia.org/wiki/File:Eunotosaurus_africanus90137.webp <- contains ICC information
https://commons.wikimedia.org/wiki/File:Meintest.webp <- contains EXIF XMP ICC information
https://commons.wikimedia.org/wiki/File:Strand%C3%BCbergang_57_5.webp contains:
VP8 Version : 0 (bicubic reconstruction, normal loop)
Horizontal Scale : 0
Vertical Scale : 0
like many but not all webp files
https://upload.wikimedia.org/wikipedia/commons/8/8d/Debbielo2.webp <- ICC
https://commons.wikimedia.org/wiki/File:LHB_coaches_.webp <-- ICC, webp flags, VP8 version
https://commons.wikimedia.org/wiki/File:Universiade_(%E5%A4%A7%E8%BF%90)_Exit_A_F1_(2022-08-16).webp <- full EXIF from Xiaomi device with GPS and date information

This is correct. Metadata extraction for webp (other than the actual webp information) is not extracted and not supported right now: https://gerrit.wikimedia.org/r/plugins/gitiles/mediawiki/core/+/refs/heads/master/includes/media/WebPHandler.php#99

The specification for anyone interested in implementing this is:
https://developers.google.com/speed/webp/docs/riff_container

Small additional problem.. our EXIF parsing depends on PHPs exif parsing, and i'm not entirely sure if php supports parsing EXIF from webp files.....

In either case: the thumbs generated by MediaWiki (as png, which is also wrong) do contain the EXIF data from the uploaded webp file. I assume that the database table in MediaWiki that contains EXIF metadata also contains the full EXIF (and can be queried from the API).

In T338341#8917011, @C.Suthorn wrote:

I assume that the database table in MediaWiki that contains EXIF metadata also contains the full EXIF (and can be queried from the API).

You assume wrong.

Ok, you are right. No EXIF is extracted. But some Metadata is found while uploading: lossless, not animated, no transparency, width, height, webp version, datetime, bitdepth -- and not even this information is displayed int the metadata section of file description pages (and thumbs do handle the full EXIF, IXX XMP)

{"result":"Success","stage":"assembling","filekey":"1a496o0w65wg.smh3q0.6080484.webp","imageinfo":{"timestamp":"2023-06-07T16:13:26Z","size":23093020,"width":8064,"height":3024,"canonicaltitle":"File:20230607161325!chunkedupload 4318e82e5e7f.webp","url":"https://commons.wikimedia.org/wiki/Special:UploadStash/file/1a496o0w65wg.smh3q0.6080484.webp","descriptionurl":"https://commons.wikimedia.org/wiki/Special:UploadStash/file/1a496o0w65wg.smh3q0.6080484.webp","sha1":"90f7907467a47da18e8710ef6bec00fad877eb76","metadata":[{"name":"compression","value":"lossless"},{"name":"animated","value":false},{"name":"transparency","value":false},{"name":"width","value":8064},{"name":"height","value":3024},{"name":"metadata","value":[{"name":"_MW_WEBP_VERSION","value":1}]}],"commonmetadata":[],"extmetadata":{"DateTime":{"value":"2023-06-07 16:13:26","source":"mediawiki-metadata","hidden":""},"ObjectName":{"value":"20230607161325!chunkedupload 4318e82e5e7f","source":"mediawiki-metadata"},"CommonsMetadataExtension":{"value":1.2,"source":"extension","hidden":""},"Categories":{"value":"","source":"commons-categories","hidden":""},"Assessments":{"value":"","source":"commons-categories","hidden":""}},"mime":"image/webp","bitdepth":0}}