via make.wordpress.org => original post link
WebP is a containerized graphics format that works with both lossy and lossless compression. Originally from On2 Technologies, it is now being developed by Google under the BSD license.
The format intends to be a new open standard for true-color graphics with lossy compression, and is therefore being presented as a direct competitor to JPEG, which expects to be outperformed in the production of smaller file sizes with comparable image quality.
WordPress 5.8+ supports the WebP image format.