Enabling Webp file format in piwigo

Piwigo does not have support for webp file format by default, but apparently it is something that can be enabled by editing a few files. See New image formats support - WebP, AVIF, Heic · Issue #1144 · Piwigo/Piwigo · GitHub

However, I’m a bit lost how I should go about this in my shiny liso server. Can anyone help?