I have already done some research and have not found anything related to my specific problem.
Quite some time ago I installed Imagick on my VPS and thus enabled the use of the Webp image format in the image transformations (Also selectable in the dropdown menu when setting up a transformation). The project I set it up for is still running on Craft 3 and the webp transforms still work fine.
Now I have multiple Craft 3/4 projects set up on the same server, and although "Webp Support" is enabled in CP > PHP Info, only jpg, png and gif can be selected as the format in the transforms.
For all Craft installations (whether v3 or v4) this info applies:
- PHP version: 8.0.25
- Image driver & version: Imagick 3.7.0 (ImageMagick 6.9.10-68)
- WebP Support: Enabled
- System requirements: All checked
Am I missing something obvious? I also don't remember setting up anything special in the installation where it works fine.
If any other info is needed, I'll be happy to provide it. :)
Edit: Looking at PHP Info in CP again, I noticed that "WEBP" is not listed in "ImageMagick supported formats". This applies to all installations, including the one where webp is shown as a format option in the transformations dropdown and it's just working fine.