WebP is a raster graphics file format developed by Google intended as a replacement for JPEG, PNG, and GIF file formats. It supports both lossy and lossless compression, as well as animation and alpha transparency. Google announced the WebP format in September 2010, and released the first stable version of its supporting library in April 2018.
The format has spotty support across applications and some vulnerabilities were discovered that required patch efforts last year. It's not clear why you should do anything.